LIBRARY 


University  of  California. 


Cla^s 


Intematiojral  €tnxtutian  Btxm 

EDITED  BY 

WILLIAM  T.  HARRIS,  A.  M.,  LL.  D. 


Volume  XL  VIII 


INTERNATIONAL  EDUCATION  SERIES. 

12nio,  cloth,  uniform  binding. 

'PHE  INTERNATIONAL  EDUCATION  SERIES  was  projected  for  the  par- 
-^  pose  of  bringing  together  in  orderly  arrangement  the  best  writings,  new  and 
old,  upon  educational  subjects,  and  presenting  a  complete  course  of  reading  and 
training  for  teachers  generally.  It  is  edited  by  William  T.  Harris,  LL.  D., 
United  States  Commissioner  of  Education,  who  has  contributed  for  the  different 
volumes  in  the  way  of  introduction,  analysis,  and  commentary.  The  volumes  art 
tastefully  and  substantially  bound  in  uniform  style. 

VOLUMES  NOW  HEADY. 

1.  The  Philosophy  of  Education.    By  Johann  K.  Y.  Rosknkranz.  Doc 

tor  of  Theology  and  Professor  of  Philosophy,  University  of  KOnigsberg. 
Translated  by  Anna  C.  Brackett.  Second  edition,  revised,  with  Com- 
mentary and  complete  Analysis.    $1.50. 

2.  A  History  of  Education.     By  P.  V.  N.  Painter,  A.  M.,  Professor  of 

Modem  Languages  and  Literature,  Roanoke  College,  Va.    $1.50. 

3  The  Klse  and  Early  Constitution  of  Universities.  With  a  Srn- 
VEY  OP  Medieval  Education.  By  S.  S.  Laurie,  LL.  D.,  Professor  of 
the  Institutes  and  History  of  Education,  University  of  Edinburgh.    $1.50. 

4.  The  Ventilation  and  Warming:  of  School  Buildings.  By  Gilbert 
B.  Morrison,  Teacher  of  Physics  and  Chemistry,  Kansas  City  High  School. 
$1.00. 

B.  The  Education  of  Man.  By  Friedrich  Froebel.  Translated  and  an- 
notated by  W.  N.  Hailmann,  A.M.,  Superintendent  of  Public  Schools, 
La  Porte,  Ind.    $1.50. 

6.  Elementary  Psychology  and   Education.     By  Joseph   Baldwin, 

A.  M.,  LL.  D.,  authoY  of  "  The  Art  of  School  Management."    $1.50. 

7.  The  Senses  and  the  Will.    (Part  I  of  "The  Mind  of  the  Child.''') 

By  W.  PRETER,  Professor  of  Physiology  in  Jena.  Translated  by  H.  W. 
Brown,  Teacher  in  the  State  Normal  School  at  Worcester,  Mass.    $1.50. 

8.  Memory :  Wliat  it  is  and  How  to  Improve  it.      By  David  Kat, 

F.  R.  G.  S.,  author  of  "  Education  and  Educators,"  etc.     $1.50. 

9.  The  Development  of  the  Intellect.    (Part  n  of  "  The  Mind  of  the 

Child.")  By  W.  Preyer,  Professor  of  Physiology  in  Jena.  Translated  by 
H.W.Brown.    $1.50. 

10.  How  to  Study  Geography.     A  Practical  Exposition  of  Methods  and 

Devices  in  Teaching  Geography  which  apply  the  Principles  and  Plans  of 
Ritter  and  Guyot.  By  Francis  W.  Parker,  Principal  of  the  Cook  County 
(Illinois)  Normal  School.    $1.50. 

11.  Education  in  the  United  States :  Its  History  from  the  Earliest 

Settlements.  By  Richard  G.  Boone,  A.M.,  Professor  of  Pedagogy, 
Indiana  University.    $1.50. 

12.  European  Schools ;  or.  What  I  Saw  in  the  Schools  of  Germany, 

France,  Austria,  and  Switzerland.  Bv  L.  R.  Klemm,  Ph.  D.,  Principal 
of  the  Cincinnati  Technical  School.    Fully'illustrated.    $2.00. 

13.  Practical  Hints  for  the  Teachers  of  Public  Schools.    By  Geoboe 

Howland,  Superintendent  of  the  Chicago  Public  Schools.    $1.00. 

14.  Pestalozzi :  His  Life  and  Work.    By  Roger  db  Guimps.     Authorized 

Translation  from  the  second  French  edition,  by  J.  Russell,  B.  A.  With  an 
Introduction  by  Rev.  R.  H.  Quick,  M.  A.    $1.50. 

15.  School  Supervision.    By  J.  L.  Pickard,  LL.  D.    $1.00. 

16.  Higher  Education  of  W^omen  in  Europe.   By  Helens  Lanob,  Berlin 

Translatedand  accompanied  by  comparative  statistics  by  L.  R.  Elbhm.  $1.00. 

17.  Essays  on  Educational  Keformers.       By  Robert  Herbert  Quiojt, 

M.  A.,  Trinity  College.  Cambridge.  Only  authorized  edition  of  the  work  aa 
rewritten  in  1890.    $1.50. 

18.  A  Text-Book  in  Psychology.  By  Johann  Friedbich  Hkbbabt.   Trans- 

lated by  Margaret  K.  Smitj.    $1.00. 


THE  INTERNATIONAL  EDUCATION  SERIES.— (ConHnued.) 

19.  Psychology  Applied  to  the  Art  of  Teachinsr.    By  Joseph  Baldwin. 

A.M.,LL.D.    $1.50. 

20.  Kousseau'8  Smile;  ob,  Treatise  on  Education.    Translated  and  an- 

notated by  W.  H.  Pattnk,  Ph.  D.,  LL.  D.    $1.50. 

21.  The  Moral  Instruction  of  Children.    By  Felix  Adler.    $1.50. 

22.  English  Education  in  the  Elementary  and  Secondary  SchoolSo 
i  By  Isaac  Sharplbss,  LL.  D.,  President  of  haverford  College.    $1.00. 

23.  Education  frona  a  National  Standpoint.  By  Alfred  FouiLLfE.  $1.50. 

24.  Mental  Development   of  the   Child.      By  W.  Preyek,  Professor  of 

Physiology  in  Jena.     Translated  by  H.  W.  Brown.    $1.00. 

25.  How  to  Study  and  Teach  History.    By  B.  A.  Hinsdale,  Ph.  D.,  LL.  D., 

University  of  Michigan.     $1.50. 

26.  Symbolic  Education.    A  Commentary  on  Froebel's  "  Motheb-Plat." 

By  Susan  E.  Blow.    $1.50. 

27.  Systematic  Science  Teaching.     By  Edward  Gardnier  Howe.    $1.50. 

28.  The  Education  of  the  Greek  People.     By  Thomas  Davidson.    $1.50. 

29.  The  Evolution  of  the  Massachusetts  Public-School  System.    By 

G.  H.  Martin,  A.  M.    $1.50. 

30.  Pedagogics  of  the  Kindergarten.  By  FriedrichFroebel.  12too.  $1.50. 

31.  The  Mottoes  and  Commentaries  of  Freldrich  Froebel's  Mother-> 

Play.    By  Susan  E.  Blow  and  Henrietta  R.  Eliot.    $1.50. 
82.  The  Songs  and   Music  of  Froebel's   Mother-Play.    By  Susan  E. 
Blow.    $1.50. 

33.  The  Psychology  of  Number,  and  its  Application  to  Methods  of 

Teaching  Arithmetic.  By  James  A.  McITellam,  A.M.,  and  John 
Dewet,  Ph.  D.     $1.50. 

34.  Teaching  the  lianguage-Arts.      Speech,  Readino,  Composition.    By 

B.  A.  Hinsdale,  Ph.  D.,  LL.  D.    $1.00. 

85.  The  Intellectual  and  Moral  Development  of  the  Child.    Part  L 

Containing  Chapters  on  Perception,  Emotion,  Memory,  Imagination, 
and  Consciousness.  By  Gabriel  Compayk§.  Translated  from  th© 
French  by  Mary  E.  Wilson.    $1.50. 

86.  Herbart's  A  B  C  of  Sense-Perception,  and  Introductory  Works 

By  William  J.  Eckopf,  Ph.  D.,  Pd.  D.    $1.50. 

87.  Psychologic  Foundations  of  Education.    By  Williak   T.  Harris, 

A.  M.,  LL.  D.     $1.50. 

88.  The  School  System  of  Ontario.    By  the  Hon.  George  W.  Ross,  LL.D., 

Minister  of  Education  for  the  Province  of  Ontario.    $1.00. 

89.  Principles  and  Practice  of  Teaching.    By  James  Johonnot.    $1.50. 

40.  School  Management  and  School  Methods.     By  Joseph  Baldwin. 

$1.50. 

41.  Froebel's    Educational    L,aws    for    all    Teachers.     By   James   L. 

Hughes,  Inspector  of  Schools,  Toronto.     $1.50. 

42.  Bibliography  of  Education.    By  Will  S.  Monroe,  A.  B.    $2.00. 

43.  The  Study  of  the  Child.    By  A.  R.  Taylor,  Ph.  D.    $1.50. 

44.  Education  by  Development.    By  Friedrich  Fboebel.    Translated  by 

Josephine  Jabtis.    $1.50. 

45.  liCtters  to  a  Mother.    By  Susan  E.  Blow.    $1.50. 

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tos, Ph.D.    $1.00. 

47.  The  Secondary   School   System   of    Germany.     By  Fbedebick  E. 

Bolton.    $1.50. 

otheb  volumes  in  preparation. 


D.  APPLETON  and  COMPANY,  NEW  YORK. 


INTERNATIONAL  EDUCATION  SERIES 


ELEMENTARY   SCIEN^OE 

BEING  PART  II  OF 

SYSTEMATIC  SCIENCE  TEACHING 

A  MANUAL  OF  INDUCTIVE 
ELEMENTARY  WORK 


BY 

EDWARD   GARDNIER  HOWE 

AUTHOR  OP  SYSTEMATIC  SCIENCE  TEACHING 


NEW   YORK 

D.    APPLETON    AND    COMPANY 

1900 


^fAdm  mm 


Copyright,  1900, 
By   D.   APPLETON   AND   COMPANY. 


Electrotyped  and  Printed 

AT  THE  ApPLETON  PreSS,  U.  S.  A. 


EDITOK'S  PEEFACE. 


Ik  my  preface  to  the  former  volume  *  I  have  dis- 
cussed the  subject  of  cultivating  observation.  It  is 
admitted  on  all  hands  that  school  training  should 
cultivate  habits  of  observation,  but  when  the  next 
question  is  considered,  namely,  the  best  method  of 
accomplishing  this,  serious  difficulties  arise.  The 
readiest  answer  to  the  question  is  found  in  the  epi- 
gram, "  Learn  to  see  by  seeing,  learn  to  observe  by 
observing."  To  the  thoughtful  person,  however,  it 
occurs  at  once  that  the  acute  seeing  of  the  hawk  or 
greyhound  does  not  lead  to  a  scientific  knowledge, 
and  that  persons  with  excellent  seeing  and  hearing 
capacity  in  general,  but  without  scientific  training, 
are  always  very  poor  observers.  More  than  this,  an 
education  in  science,  although  it  fits  a  person  to  ob- 
serve in  the  line  of  his  own  specialty,  does  not  fit 
him  to  observe  in  the  line  of  another  science  which 


*  Systematic  Science  Teaching,  vol.  xxvii  of  the  International 
Education  Series. 

V 


214720 


vi  SYSTEMATIC  SCIENCE  TEACHING. 

he  has  not  investigated.  On  the  contrary,  the  train- 
ing in  one  particular  line  rather  tends  to  dull  the 
general  power  of  observation  in  other  provinces  of 
facts.  The  archaeologist  Winckelmann,  cited  by  me 
in  the  preface  referred  to,  could  recognize  a  work 
of  art  by  a  small  fragment  of  it,  but  it  does  not 
follow  that  he  could  observe  a  fish's  scale  and  recog- 
nize the  fish  to  which  it  belonged.  On  the  other 
hand,  Agassiz  could  recognize  a  fish  from  one  of  its 
scales,  but  could  not,  like  Winckelmann,  recognize  a 
work  of  art  from  one  of  its  fragments. 

In  studying  the  lessons  in  botany,  which  are  skill- 
fully arranged  by  Mr.  Howe  in  this  book,  the  pupil 
will  be  greatly  helped  in  his  power  of  observation  of 
the  plant  world,  and,  compared  with  one  of  his  fel- 
lows who  has  not  studied  botany,  he  will  observe  from 
week  to  week  and  year  to  year,  and  retain  in  his 
memory,  thousands  of  particulars  in  regard  to  the 
plants  which  he  sees  in  his  environment,  and  which 
his  fellow-pupil  would  pass  entirely  unnoticed. 

This  is  equally  true  as  regards  the  lessons  on  min- 
erals and  rocks,  on  the  stars  and  the  earth,  and  on 
the  animal  kingdom.  The  power  of  observation  will 
be  sharpened  to  such  a  degree  that  the  pupil  will 
become  observant  in  a  hundred  new  ways.  Traveling 
in  southern  Texas  on  a  midwinter  night  his  attention 
would  be  drawn  to  a  bright  star  near  the  southern 
horizon,  pretty  nearly  on  the  meridian  of  the  constel- 


EDITOR'S  PREFACE.  vii 

lation  Orion.  He  would  be  likely  to  remember  that 
in  former  studies  of  the  star  map  his  attention  had 
been  called  to  a  star  of  the  first  magnitude,  very  fa- 
miliar to  stargazers  in  the  southern  hemisphere,  and 
he  would  inquire  eagerly,  "  Is  this  not  Canopus,  once 
thought  to  be  the  nearest  of  all  fixed  stars  to  the 
earth?"  The  person  who  had  never  made  these 
amateur  studies  in  astronomy  would,  on  a  similar 
journey,  glance  without  interest  or  special  attention 
at  the  bright  reddish  star  eight  or  ten  degrees  above 
the  southern  horizon.  Illustrations  like  these  will 
readily  occur  to  any  one  who  has  considered  the  true 
method  of  cultivating  observation.  It  is  not  percep- 
tion pure  and  simple  that  makes  observation,  but  it 
is  rather  what  is  called  apperceptioii  (the  use  of  the 
stored-up  results  of  the  aggregate  perception  of  the 
race)  that  gives  one  power  to  see  new  objects  and  ex- 
plain familiar  objects. 

It  is  hoped  by  the  publishers  that  this  new  volume 
will  meet  with  the  gratifying  reception  accorded  to 

the  former  volume. 

W.  T.  Harris. 

"Washington,  D.  C,  January  S5, 1900. 


AUTHOE'S  PKEFACE. 


Science  teaching  has  made  great  progress  of 
late  years,  and  the  conclusions  in  the  preface  to  my 
former  volume  need  no  modification  here. 

Encouraged  by  the  kindly  words  of  the  press  and 
of  teachers  regarding  Volume  I  for  the  primary 
grades,  the  present  volume  has  been  prepared  to  pro- 
vide a  symmetrical  graded  course  in  natural  science 
for  the  higher  grades  of  the  grammar  school. 

It  is  confidently  hoped  that  my  labors  may  prove 
an  efficient  aid  and  suggestion  to  teachers  and  school 
officers  in  establishing  definite  and  progressive  graded 
work,  and  thereby  hasten  the  day  when  instructors  of 
natural  science  in  our  high  schools  and  colleges  may 
be  able  to  base  their  work  upon  as  substantial  a  basis 
of  preparation  as  do  those  in  language  and  mathe- 
matics. 

Only  as  this  is  done,  can  the  subject  become  the 
educational  factor  which  its  peculiar  relation  to  the 
child,  its  subject-matter,  and  its  methods  so  aptly  fit 
it  to  be. 

ix 


X  SYSTEMATIC  SCIENCE  TEACHING. 

My  thanks  are  due  to  so  many  teachers  and  ex- 
perts for  kindly  advice  and  criticism,  that  I  can  only 
ask  each  to  accept  my  grateful  acknowledgment  in 
proportion  to  his  aid.  To  Dr.  William  T.  Harris  and 
my  publishers  I  am  under  especial  obligations  for 
their  unfailing  courtesy  and  kindness  through  all 
the  difficulties  incident  to  the  editing  and  printing 
of  a  book  of  this  character. 

Edward  G.  Howe. 
University  of  Illinois, 
Uebana,  January,  1900. 


The  Relation  of  the  Several 


Year  of 
Work. 


A.  The  Stars 
AND  Earth. 


B.  Minerals  and  Rocks. 


1st. 


The  Skies  (general).    II. 
Early  winter.    10  lessons. 


Metals      sorted. 
Winter.    12  lessons. 


III. 


2d.  The  Moon.    VII.    Win- 

ter.   10  lessons. 


Minerals  sorted.    VIII. 
Winter.     15  lessons. 


3d.  The  Earth.  XVI.  Spring. 

20  lessons. 


Minerals  and  Rocks  sort- 
ed. XIV.  Winter.  15 
lessons. 

Pebbles.  XV.  Winter. 
30  lessons. 


4th.  The  Earth  {continued). 

XXII.     Late  spring.     25 
lessons. 


How  Sharp  Stones  came 
to  be.  XX.  Winter.  20 
lessons. 

Plane  Form  and  Color. 
XXI.    Winter.    20  lessons. 


5th.  The       Solar       System. 

XXIV.    Early  winter.    25 
lessons. 


Metals  studied.  XXV. 
Winter.    20  lessons. 

Solid  form.  XXVI.  Win- 
ter.    20  lessons. 


6th.  Gravitation.  XXX.  Late 

fall.    20  lessons. 


Molecule  Lessons.  XXXI. 
Winter.    30  lessons. 


7th.  Light,  Telescope,  Spec- 

troscope, Laplace.  XXXV. 
Late  fall.    30  lessons. 


Crystals.  XXXVL  Win- 
ter.   20  lessons. 

Minerals  studied. 
XXXVn.  Winter.  30 
lessons. 


8th.  The    Early   Plistorv  of 

the  Earth.   "XLIL    Win- 
ter.   25  lessons. 


Coins.  XLIII.  Win- 
ter.    10  lessons. 

Earth-making.  XLIV. 
Spring.     40  lessons. 


9th.  Other      Systems     than 

Ours.  XLVIL         All 

through  year.    20  lessons. 


Rocks.    XLVin. 
ter.     50  lessons. 


Win- 


Xll 


Steps  to  Each   Other. 


G.  Plants. 


D.  Animals. 


Sorting  Seeds  and  Fruits.  1. 
Autumn.    20  lessons. 

Buds.  IV.  Spring.  15  les- 
sons. 


Eight  Home 
Early  summer. 


Animals.    V. 
35  lessons. 


Roots  and  Stems.  VI.  Au- 
tumn.    10  lessons. 

Typical  Leaves.  X.  Early 
summer.     15  lessons. 


Twenty-three  Familiar  Ani- 
mals of  Spring  and  Moral  Les- 
sons connected.  IX.  Spring. 
50  lessons. 


Trees.  XII.  Autumn.  121es. 

Woods  and  Barks.  XI IL 
Winter.     15  lessons. 

Flowers.  XVII.  Late 
spring.    25  lessons. 


Thirty-three  Foreign  and 
'Less  Familiar  Animals.  XI. 
Autumn.    50  lessons. 


Fruits  studied.  XVIII.  Au- 
tumn.   25  lessons. 


Boy  studied.    XIX. 
winter.    40  lessons. 


Early 


The  Life  History  of  One 
Plant.  "  Morning-glory  Les- 
sons." XXin.  Autumn.  45 
lessons. 


Boy  Study  applied  to  a  Se- 
ries of  Typical  Animals. 
XXVII.  Late  spring.  60  les- 
sons. 


Relationships  of  Plants. 
XXVIII.  Autumn.  30  les- 
sons. 

(Toman,  see  Step XXXII.) 


Winter  Quarters  of  Animals. 
XXIX.  Late  autumn.  20  les- 
sons. 

Man  at  Home.  XXXIL 
Spring.    40  lessons. 


Winter  Quarters  of  Plants. 
XXXIV.  Autumn.   30  lessons. 


Life  Histories  of  Types. 
XXXVIII.  Late  spring.  25 
lessons. 


Partsand  Structure  of  Fruits. 
XL.     Autumn.   20  lessons. 

Corn  and  Beans.  XLI.  Au- 
tumn.   20  lessons. 


Life  Histories  of  Types  {con- 
tinued). XXXIX.  Time  and 
lessons  as  required. 


Important  Familiesof  Plants 
at  Sight.  XLV.  Spring.  25 
lessons. 

Important  Families.  XLVI. 
Autumn.     25  lessons. 


Animal     Groups. 
Spring.    40  lessons. 


XLIX. 


SYSTEMATIC   SCIENCE   TEACHING. 
PART  II. 


STEP  XXIV.— THE  SOLAR  SYSTEM. 

So  far,  the  general  survey  of  Step  II  led  to  a  study  of 
the  moon  and  months  (Step  VII) ;  that,  to  the  earth's 
daily  motion,  day  and  night,  and  longitude  and  time  in 
Step  XVI.  Continuing,  came  in  Step  XXII  the  yearly 
motion  of  the  earth  and  inclination  of  its  axis  to  the 
ecliptic,  resulting  in  the  year,  with  its  varying  day  and 
night,  heat  and  cold,  causing  the  four  seasons,  and  de- 
termining the  position  of  the  five  parallels  of  latitude 
to  which  all  others  must  agree. 

These  steps  follow  each  other  in  easy,  logical  order; 
and  now  we  shall  proceed  to  consider  the  earth  as  a 
member  of  a  family  called  The  Solar  System.  How 
truly  its  parentage  is  shown  by  the  name  will  appear  in 
Step  XXXIV.  Another  purpose  in  this  star  work,  espe- 
cially on  the  constellations,  is  to  improve  the  eyesight  by 
long-range  vision.  So  much  of  the  school  work  and 
city  seeing  is  at  short  range  as  to  prove  a  serious  injury 
to  the  eyes,  and  it  is  believed  by  good  authorities  that  the 
cultivation  of  habits  of  long-range  sight  will  do  much  to 
counteract  this. 

The  Time  needed  will  be  about  twenty-five  lessons  of 
fifteen  to  twenty  minutes  each,  but  much  of  this  will  be 
reading.  I  have  arranged  the  step  to  come  in  November, 
when  the  constellations  can  be  seen. 

2  1 


2  SYSTEMATIC  SCIENCE  TEACHING. 

Material — Some  good  drawing  paper,  pencil-pointed 
compasses,  and  water  colors  (see  XXX)  will  be  needed, 
besides  the  globes.  Get  for  the  use  of  the  class  as  many- 
telescopes,  "  spy,"  field,  or  opera  glasses,  as  can  be  found. 
The  very  poorest  will  be  helpful. 

Preparation  of  the  Teacher.— But  little  need  be  added 
to  the  suggestions  of  Step  XVI.  Review  previous  steps, 
read  in  books  about  the  solar  system,  the  remaining  six 
zodiacal  constellations,  and  go  through  this  step  care- 
fully before  beginning  with  the  class. 

The  Lessons. 

ftnestion  briefly  on  the  past  steps  to  make  the  connec- 
tion, as  follows : 

What  is  the  shape  of  the  sun  ?    The  moon  ? 

Why  does  the  moon  seem  to  change  its  shape  ? 

Is  the  light  of  the  moon  its  own,  or  borrowed  ? 

Which  way  does  the  moon  travel  around  the  earth  ? 

Why  is  the  month  about  thirty  days  long  ? 

Name  the  months  in  order. 

What  do  some  of  these  names  mean  ? 

What  proofs  have  we  that  the  earth  is  spherical  ? 

Tell  of  an  experiment  which  shows  its  revolution  on 
its  axis. 

Why  is  our  day  twenty-four  hours  long  ? 

What  were  some  of  the  ancient  ways  of  telling  time  ? 

Give  the  names  of  the  days  of  the  week. 

Why  do  the  sun  and  moon  seem  to  rise  in  the  east  ? 

How  do  we  know  the  earth  is  traveling  around  the 
sun  ? 

Where  did  we  get  the  year  of  365^  days  ? 

What  is  an  eclipse  ?    How  caused  ? 

What  causes  the  days  and  nights  to  vary  in  length  ? 

How  much  is  the  axis  inclined  ? 

What  parallels  are  23^°  from  the  poles  ?  From  the 
equator  ? 


THE  SOLAR  SYSTEM.  3 

Name  the  four  seasons  and  their  meaning. 

Why  is  winter  cold  and  summer  warm  ? 

Why  is  the  sun  said  to  "  pass  through  "  such  and  such 
constellations  ? 

Does  he  really  do  so  ? 

Describe  our  illustration  with  pictures  on  the  wall. 

What  is  the  belt  through  which  the  sun  seems  to  pass 
called  ? 

Name  its  twelve  constellations,  beginning  with  Aprils. 

The  north  pole  points  to  what  star  ?    (Pole  star.) 

To  what  constellation  do  the  "  pointers "  belong  ? 
(Great  Bear.) 

What  bright  star  do  those  of  the  Bear's  tail  lead  to  ? 
(Arcturus.) 

What  semicircle  of  stars  near  Arcturus  ? 

What  mighty  hero  is  next  the  Crown  ? 

What  skin  is  Hercules  supposed  to  wear  ? 

Where  is  the  Lion,  and  how  known  ? 

Where  is  the  Hydra  ? 

If  Draco  guards  the  Golden  Apples,  where  must  they 
lie  ?    (Near  the  Little  Bear.) 

What  group  east  of  the  Lion  in  May  ? 

What  does  the  Virgin  hold  in  her  hands  ? 

East  of  the  Scales  lies  what  group  ? 

Constellation  east  of  Scorpio  in  July  ? 

What  does  Sagittarius  represent  ? 

How  can  Capricornus  be  distinguished,  and  where  ? 

Other  Planets. 

Get  almanacs,  and  find  which  are  to  be  seen,  and 
when.  The  planets  Venus  and  Jupiter  are  most  easily 
seen,  and  they  should  be  watched  to  see  that  their  posi- 
tion among  the  constellations  changes.  Mars  and  Sat- 
urn are  conspicuous,  but  not  quite  so  much  so  as  Jupiter. 

Let  the  class  make  diagrams  in  their  notebooks  of 
the  positions  once  a  week  till  the  motion  is  easily  noted. 


4  SYSTEMATIC  SCIENCE  TEACHING. 

What  does  the  word  "  planet "  mean  ?  (Wanderer.) 
Why? 

Which  way  do  they  "  wander  "  ? 

This  might  be  found  by  observing  for  some  time, 
especially  if  opera  glasses  were  used,  but  I  would  advise 
showing  the  class  such  pictures  (those  on  p.  136,  Lock- 
yer,  or  pp.  186  and  192,  Burritt)  as  will  illustrate  the 
phases  of  some  of  the  planets. 

These  will  at  once  suggest  the  moon  and  the  ques- 
tion whether  the  planets  revolve  about  the  earth. 

Now  take  the  lamp  and  little  globe  and  follow  the 
plan  in  Lockyer's  Astronomy  Primer,  pp.  56-59,  and  I 
think  any  class  can  be  led  to  see  that  no  planet  revolving 
between  us  and  the  sun  can  be  seen  at  midnight  (as  we 
can  the  moon),  and  must  be  either  a  "morning"  or 
"  evening  star,"  having  phases  like  the  moon. 

Also,  that  any  planet  farther  from  the  sun  than  we, 
and  so  nearest  to  us  when  opposite  the  sun,  will  always 
show  a  bright  face  to  us.  No  "moon"  could  ever  ap- 
pear in  either  of  these  ways,  and  as  some  "  wanderers  " 
show  decided  phases  and  are  only  seen  for  two  or  three 
hours  at  either  morning  or  evening,  and  never  at  mid- 
night, we  know  there  are  "  interior  "  planets. 

As  other  "  wanderers  "  are  brightest  when  seen  oppo- 
site the  sun,  and  never  distinctly  show  the  "  horns  "  of  a 
new  or  old  moon,  we  know  there  are  "  exterior  "  planets. 

How  many  of  each  kind  are  there  ? 

Astronomers  (those  men  and  women  who  study  these 
things  and  think  carefully  about  them)  have  found  out 
much,  and  we  will  go  to  their  books  to  see. 

How  many  do  they  say  ?  ("  Two  interior,  the  earth, 
and  live  large  exterior  planets — eight  in  all.") 

Relative  Size  of  the  Planets. 

How  large  are  they,  compared  with  the  sun  ? 

All  have  been  carefully  measured,  and  let  us  first  try 
to  get  an  idea  of  how  large  the  sun  is. 


THE  SOLAR  SYSTEM.  5 

Class  draw  Diagram  1. 

Sun's  diameter  =  850,000  miles.  Eepresent  by  a  circle 
with  43  mm.  radius. 

Moon's  orbit  =  480,000  miles.  Represent  by  a  circle 
with  24  mm.  radius. 


Fro.  1. — Size  ob'  the  Sun. 
Sun  850.000  miles  =  84  mm.  =  42  mm.  radius;  Moon's  orbit 
480.000  miles  =  48  mm.  =  24  mm.  radius.    If  the  sun  were 
hollow  and  the  e  at  the  center,  there  would  be  room  for 
the  f)  's  orhit  and  200,000  miles  outside. 

Place  the  earth  (©)  at  the  center,  and  the  moon  (f)) 
on  her  orbit. 

Color  the  sun  (outside  moon's  orbit)  a  bright  yellow 
or  oranore. 


6  SYSTEMATIC  SCIENCE  TEACHING. 

Color  the  moon's  orbit  with  a  wash  of  blue. 
Write  neatly  below  what  the  card  represents. 
Diagram    2. — Describe    circle  with    50  mm.   radius. 
Draw  a  very  light  line  across  (diameter),  and  mark  it 


Fig.  2. — Size  of  the  Sun. 
If  a  hole  the  size  of  the  e  were  bored  through  the  0  and  e's 
dropped  in,  it  would  take  100  ®'s  to  fill  the  hole, 
low,  the  O  would  hold  over  1,000,000  ©'s. 


If  hol- 


into  100  spaces  with  a  mm.  scale.  Make  a  little  circle 
on  each  space  to  represent  the  earth,  100  of  which  equal 
in  diameter  the  large  circle.    On  the  top  place  a  "  knife 


THE  SOLAR  SYSTEM.  7 

edg-e  "  (A)  and  evenly  on  it  a  10-cra.  line.  Draw  pans  at 
either  end,  and  in  one  write  "sun"  and  in  the  other 
'•  300,000  earths."  Color  to  suit  taste,  and  write  what  it 
represents. 


Fig.  3. — Relative  Size  of  Sun  and  Planets. 

O,  84mra. ;    5,  i  mm.;    5,  1  mm.;  e,  1  mm.;    5,i  mm.;  y, 

8  mm. ;  ^  ,  7  mm.,  ring  17  mm. ;  Jj^,  3^  mm. ;   f  ,  4^  mm. 

Diagram  3.— With  42  mm.  radius,  draw  a  circle  to 
represent  the  sun.  On  two  faint  horizontal  lines,  extend- 
ing, the  one  above  and  the  other  below  the  center,  rep- 
resent the  eight  planets  as  follows : 

Mercury  ( ^  )  by  a  dot.     Color,  oranj^e. 

Venus  (?)  by  a  dot  1  mm.  in  diameter.   Color,  green. 


8  SYSTEMATIC  SCIENCE  TEACHING. 

Earth  (©)  by  a  dot  1  ram.  in  diameter.     Color,  green. 

Mars  (3)  by  a  dot  i  mm.  in  diameter.     Color,  red. 

Jupiter  (2f )  by  a  dot  8  mm.  in  diameter.  Color,  pale 
red. 

Saturn  ( ^ )  by  a  dot  7  and  ring  17  mm.  in  diameter. 
Color,  blue  and  ring  white. 

Uranus  (iff.)  by  a  dot  3^  mm.  in  diameter.  Color,  pale 
blue. 

Neptune  ( T )  by  a  dot  4  mm.  in  diameter.  Color,  pale 
blue. 

Having  drawn  (in  light  lines)  the  planets,  color  the 
whole  the  bright  yellow  or  orange  which  we  have 
adopted  to  represent  the  light  and  heat  of  the  sun,  and 
when  perfectly  dry,  color  the  planets  as  indicated  above. 

Eeasons  for  the  colors  given  are  these :  Mercury  is 
difficult  to  see,  and  hot  (see  Lockyer,  p.  259) ;  Venus  is 
much  like  the  earth,  and  the  earth  is  clad  in  green ; 
Mars  is  the  *'  fiery  red  "  planet ;  Jupiter,  pale  red,  be- 
cause there  are  reasons  for  thinking  this  huge  planet 
(fourteen  hundred  times  the  size  of  the  earth)  is  still  quite 
hot.  A  cold  blue  has  seemed  most  appropriate  for  plan- 
ets distant  in  space. 

Pins  and  balls  will  still  further  illustrate  this  matter 
of  relative  size  and  distance. 

"  Mourning  pins  "  (assorted),  large-headed  shawl  pins 
or  hairpins,  marbles,  and  rubber  or  wooden  balls  can 
be  called  into  service  to  make  up  a  set.  (See  Lockyer's 
suggestion,  p.  76.) 

These  measurements  are,  of  course,  only  approxima- 
tions, but  as  near  as  need  be  required. 

Measure  the  globe  you  may  have,  and  then  find  pins 
and  balls  to  correspond.  I  would  let  each  pupil  (who 
wishes)  make  up  a  set  to  keep,  sticking  the  pins  in  a  card 
and  marking  over  each  one  what  it  represents  and  the 
size  of  globe  they  go  with.  The  class  will  now  have  an 
idea  of  the  relative  size. 


THE  SOLAR  SYSTEM. 


SUN  REPRESENTED  BY  A  GLOBE  OF 

Distances 

Diameter  of  Pin, 

ETC.,  TO    REFRESENT 

8  inches 
(200  mm.). 

12  inches 
(300  mm.). 

16  inches 
(400  mm.). 

(1  mm.  = 

18,000.000 

miles). 

Mercury  (  5  ) 

Venus(?) 

Earth  (©) 

Mars  {$) 

Jupiter  (2^) 

Saturn  (^) 

Uranus  (ijl) 

Neptune  ( t ) 

f    mm. 

2-  " 

2       " 

1       " 
20       " 
17  and  ring 

40  mm. 
7  —  mm. 
8-    " 

I  +  mm. 
2i       - 

3 

H     " 

30 
25  and  ring 
60  mm. 

II  mm. 
12     " 

li  mm. 

3i    " 

4      « 

2      " 
40      " 
34  and  80 
mm. 

15  mm. 

16  " 

2  mm. 

4  " 

5  " 
8    " 

26    " 
48    " 

97    " 
152    " 

Diagram  4.  Eelative  Distances  of  the  Planets.— Get 
pieces  of  drawing  paper  (manilla  will  do)  400  mm.  square. 
Find  the  center,  and  place  a  gilt  star  or  draw  a  sun. 
Now  describe  circles  around  this  central  sun  at  the  suc- 
cessive distances  from  its  outer  limit  that  are  given  (for 
convenience)  in  the  last  column  of  the  above  table. 

On  each  orbit  now  place  the  proper  planet — the  same 
size  as  given  in  the  table — and  color  them  as  for  Dia- 
gram 3.  We  now  have  a  very  interesting  chart  repre- 
senting the  relative  distances  (see  Lockyer,  p.  75).  Say 
nothing  of  the  moons  at  this  point,  but  save  these  charts 
to  put  them  in  later. 

Set  Fins. — Agree  on  some  scale  (1  foot  to  the  mm.  I 
use)  and  let  the  class  lay  off  these  distances  on  a  level 
fence  or  sidewalk,  and  then  stick  the  pins  (through 
paper  labels),  and  place  the  balls  in  the  proper  places. 
This  is  an  exceedingly  interesting  and  instructive  exercise, 
and  the  respect  of  the  pupils  for  the  size  of  our  planet 
"  family "  and  the  enormous  distances  between  them 
should  have  made  a  considerable  and  healthy  growth. 

This  can  be  deepened  and  broadened  by  turning  to 
page  296  of  Lockyer  and  talking  of  the  year  each  one 
has,  varying  from  87  days  for  Mercury  to  165  years  (of 
ours)  for  one  of  Neptune's. 


10  SYSTEMATIC  SCIENCE  TEACHING. 

Direction  of  Motion. — Arrows  should  be  placed  by 
each  planet  on  Diagram  4  to  show  this.  All  point  oppo- 
site to  the  motion  of  the  hands  of  a  watch. 

Plane  of  the  Ecliptic— Refer  again  to  this,  illustrat- 
ing it  in  some  such  way  as  before  given  (see  Step  XXII), 
or  by  a  sheet  of  cardboard  with  the  circles  of  Diagram  4 
on  it,  and  holes  the  proper  size  cut  to  lay  the  planets  in, 
and  then  speak  of  the  other  large  planets  (Lockyer,  p.  74). 
Mercury  and  Venus  are  the  only  ones  which  differ  much 
from  our  earth's  plane. 

Moons  of  the  other  planets. 

Let  the  class  take  Diagram  4  and  add  the  proper 
number  of  satellites  to  each  (Lockyer,  p.  75). 

The  class  may  be  interested  in  referring  to  Lockyer 
(p.  297)  and  noticing  the  size,  distance,  and  period  of 
revolution  of  these.  When  the  idea  of  such  revolution 
about  the  primary  is  before  the  class,  lead  them  to  speak 
of  Jupiter's  moons  in  particular,  and  of  the  eclipses  and 
disappearances  which  must  occur  as  the  moons  revolve 
about  the  planet  (Lockyer,  p.  145,  and  Burritt,  p.  236, 
etc.). 

Speed  of  Light. — By  circles  on  the  board,  represent 
the  sun,  earth,  and  Jupiter,  and  tell  how  Roemer's  obser- 
vations on  these  moons  when  Jupiter  was  nearest  to,  and 
farthest  from,  the  earth  led  to  the  discovery  of  the  speed 
of  light. 

Would  go  over  Roemer's  calculations  with  the  class 
(Burritt,  p.  239). 

Meaning  of  Names  and  Signs  (Lockyer,  p.  71). 

Cometa — Briefly  refer  to  these  strange  members  of 
our  "  family."     Show  pictures  and  read  about  them. 

Constellations. — Continue  those  of  the  zodiac.  Begin 
in  September  or  October  to  observe.  (See  Astronomy 
with  an  Opera  Glass ;  Serviss,  Chapters  III  and  IV.) 

Review  Capricomus  and  such  others  as  may  be  visible 
of  those  before  learned.    Then  pass  east  to 


THE  SOLAR  SYSTEM. 


11 


Aquarius,  who  is  represented  as  holding-  an  urn  from 
which  flows  a  river  of  water  down  to  where  the  southern 
Fish  swims  in  it.  Connected  with  this  constellation  are 
the  stories  of  Ganymede  (see  Burritt,  p.  132),  and  the 
overflow  of  the  Nile. 

Piscea — When  Aquarius  is  in  the  south,  this  constella- 
tion will  be  in  the  southeast.  The  stars  are  small,  and  but 
little  of  interest  is  connected  with  the  group  except  as 
being  the  first  of  the  zodiac,  and  that  in  which  the  sun 
seems  to  enter  at  the  beginning  of  spring. 

Aries  lies  east  of  the  Fishes,  and  is  most  easily 
found  by  the  two  stars  in  the  head. 

This  is  the  ram  which  bore  the  famous  fleece  of  gold. 
(Bulfinch,  p.  158 ;  Burritt,  p.  30 :  Greek  Heroes,  The  Ar- 
gonauts, and  Hawthorne's  Golden  Fleece.) 

TaTirus. — The  Bull.  As  the  Ram  gets  into  the  south, 
this  beautiful  group  will  appear  directly  east.     Not  only 


12  SYSTEMATIC  SCIENCE  TEACHING. 

are  the  stars  in  two  beautiful  clusters  (Pleiades  and 
Hyades),  but  much  interesting  history  and  fable  clus- 
ter about  them.  (See  Burritt,  p.  41 ;  Bulfinch's  Europa, 
Pleiades,  Hyades ;  and  Hawthorne's  Dragon's  Teeth,  in 
Tanglewood  Tales.)  The  mythology  might  easily  ex- 
tend to  the  Argonauts,  etc.,  but  I  have  thought  best  to 
leave  everything  but  the  groups  of  the  zodiac  here. 

As  Taurus  passes  to  the  west,  in  the  east  and  south- 
east will  arise  Geminif  or  the  Twins.  While  the  Bull  is 
on  the  west  of  the  milky  way  the  Twins  are  on  the  op- 
posite side,  and  the  group  is  peculiar  for  the  rows  or  lines 
of  stars  it  contains.  The  two  brightest  ones  are  in  the 
heads  of  the  Twins;  from  these,  rows  extend  to  a  foot 
of  each,  and  intermediate  stars  make  three  cross-bands 
in  the  heads,  knees,  and  feet.  These  brothers  had  a  re- 
markable history.  (See  Burritt,  p.  55  ;  Bulfinch :  Castor, 
etc.) 

Cancer  (the  Crab)  lies  next  east ;  not  a  brilliant 
group,  nor  having  much  that  is  interesting  to  young 
classes  about,  it.     (See  Burritt,  p.  65.) 

Review. — Question  on  what  has  been  told  and  learned. 
Hang  tlie  twelve  constellations  (diagrams)  around  the 
room,  and  repeat  the  experiment  with  lamp  and  small 
globe  (Primer,  p.  19,  etc.).  This  will  have  an  added 
interest  now. 

Next  step  in  this  study,  XXX. 


Get  from  dealer  in  chemicals. 


STEP  XXV.— METALS  STUDIED. 

The  object  of  these  lessons  is  : 

1.  A  more  intimate  acquaintance  with  metals  than 
Step  III  gave. 

2.  Advance  in  experimenting. 

3.  To  prepare  for  work  in  minerals. 

Time. — About  twenty  lessons  of  fifteen  to  twenty- 
minutes  each. 

Material— In  addition  to  that  of  Step  III,  get  the  fol- 
lowing : 

Magnesium  ribbon, 

Metallic  antimony, 

Metallic  bismuth, 

Platinum  wire, 

Aluminium  wire, 

Mercury, 

Metallic  potassium, 

Metallic  sodium. 

^  T        .  '  ,  .         t  Get  at  tinsmith's. 
Galvanized  iron.  ) 

Magnets  of  Step  III. 

The  hard-tile  streak  plates  of  Step  VIII. 

Alcohol  lamps  of  some  kind  (a  piece  of  large  glass 
tubing  through  the  cork  of  an  ink  bottle  does  nicely). 

Pincers  to  hold  the  pieces  while  heating. 

Cut  the  magnesium  into  pieces  1^  inch  long. 

Cut  the  platinum  and  aluminium  wire  into  bits  1  inch 
long. 

Break  carefully  the  antimony  and  bismuth  into 
pieces  the  size  of  a  white  bean  or  pea. 

13 


14 


SYSTEMATIC  SCIENCE  TEACHING. 


ll 

1      ^-  III             lll| 

:S'     o     --Ofciso      o3      oajiSoo      oo      o      o  u  «.2ls  a> 

la" 

Changeable 
colors. 

Cleaner  & 
brighter. 

Tarnish. 

Tarnish. 

Melts. 

Melts. 
Burns ; 

blue  flame. 

Melts. 
Smokes 

and  n.elts. 

Melts: 

Black. 

Black. 

Softer. 

fin  melts 

off. 

Burns. 

ClennerA 

brighter. 

Glows. 

Cleaner. 

Melts. 

To  Bcratch 

h  hard. 

Medium. 

Soft 

.        2yj    jj^      1 

aj    GQ    ggcQoJc/j    CCS    ccSKKS  :    ccaj    g    a:_g-^.      . 

•' 

1 

*: 
S 

1 

O 

Copper  red. 

Gold  yellow. 

Brass  yellow. 
Bronze. 
Lead  gray. 
Bluish  white. 
Grayisu  white. 

Lead  gray. 
Bluish  white. 

Reddish  white 
Grayish  white. 
Iron  black. 
Steel  gray. 
G ravish  white. 
Tin  white. 

Tin  white. 
Silver  white. 

Tin  white. 

Grayish  white. 
Silver  white. 
Reddish  white. 

Silver  white. 

5^^^ 
P 

1  II  1       ^i       &  &I 

1 1  km  rs  psiii  II 1  r 

Pound 

gently. 

Ii    malleable 

or  brittle. 

S-:  .IN 
.11 'ill 

S      cfj  -S  -^ 

-|             d     6     6  6  6  6  6     6  6      d**"?*     do     d     6  6 
^  1           Iz;    Jz;    5z;;z;!z;;z;!z;     ^55     Iz  >^  >^  Jh  >^  ><    ^555    55    Sz;^ 

g 
1 

Light. 

Medium. 

Heavy. 

1     1 

a  tij  ssffii^j  Ks  ag'ssss  std  w  Jag  | 

e 

Ii 

or 

1 

c 

s 

Magnesium... 

Type  metal... 
Antimony 

Bismuth 

Wrought  irou. 

Cast  iron 

St-eel(tool).... 

Nickel 

Tin  plate 

Tinfoil 

Silver 

Platinum 

Aluminium.. . 
Mercurv 

S 

£ 

METALS  STUDIED.  15 

Put  drops  of  mercury  the  size  of  a  pea  iu  glass  vials, 
enough  to  go  round,  and  cork  them. 

The  sodium  and  potassium  should  not  be  given  to  the 
class,  only  passed  around  at  the  last  for  examination, 
and  then  pieces  placed  on  water  by  the  teacher  to  show 
how  they  float  and  take  fire. 

See  that  all  the  metals  have  somewhere  a  clean, 
bright  surface. 

Expense.— About  five  dollars,  in  addition  to  materials 
before  suggested. 

Preparation  of  Teacher.— With  the  specimens  before 
you  in  twenty-one  boxes,  arranged  in  a  tray,  compare 
your  results  with  those  of  the  table  on  page  14. 

I  find  much  disagreement  in  books  regarding  color 
and  hardness.  A  careful  study  of  my  sets  of  specimens 
gives  the  following  results.  Other  material,  especially 
of  alloys,  will  doubtless  differ. 

The  order  in  which  I  have  arranged  the  metals  has 
aimed  to  group  those  resembling  one  another,  so  as  to 
aid  in  comparison. 

The  reasons  for  the  order  of  work  are  as  follows : 

1.  Weight,  determined  before  the  material  is  cut  or 
broken  up.* 

*  This  has  always  been  a  trouble  to  me,  from  the  difficulty 
of  getting  equal-size^  pieces  of  the  different  metals  large  enough 
for  the  hand  to  judge  of  the  relative  weights. 

I  have  tried  two  ways : 

A.  I  got  coins  of  gold,  silver,  bronze,  copper,  and  nickel  of 
nearly  the  same  size,  and  pieces  of  the  other  metals  (last  two  al- 
ways excepted),  finding  the  bulk  of  each  by  means  of  a  grad- 
uated cylinder  holding  some  water,  or,  better,  with  a  specific- 
gravity  balance.  Those  whose  specific  gravity  was  under  5,  I 
called  light ;  under  9,  medium  ;  and  over  9,  heavy. 

B.  I  kept  my  metals  in  medium-sized  glass  vials,  having 
these  all  equally  full,  and  passing  them  around  the  class  before 
giving  out  the  specimens.    Gold,  silver,  and  platinum  were  here 


16  SYSTEMATIC  SCIENCE  TEACHING. 

2.  Magnetic,  before  a  magnet  has  touched  them. 

3.  Bend,     )  These  aid  each  other,  and  the  fragments 

4.  Pound.  )       are  needed  later. 

5.  Streak)  gives  a  fresh  surface  for  6. 

6.  Color. 

7.  Hardness,  partly  shown  by  the  streak  plate. 

8.  Heat. — The  fresh  surfaces  (made  by  pounding)  will 
enable  change  of  color  through  heat  to  be  seen. 

9.  Water  is  apt  to  change  the  color,  and  so  must  be 
used  last. 

If  the  pieces  touch  or  are  near  each  other  in  the 
water,  the  rust  from  the  iron  is  apt  to 'get  on  the  others ; 
and  as  it  injures  so  many  of  the  specimens,  I  would 
advise  separate  dishes  or  shells. 

The  Lessons. 

1.  Let  some  pupil  draw  a  plan  of  the  table  (page  14) 
on  the  board,  the  names  of  the  metals  at  the  left  and 
headings  of  columns  at  the  top,  and  each  pupil  draw  one 
to  a  scale  on  large  paper. 

2.  Give  out  the  boxes  and  empty  trays,  and  direct  the 
pupils  while  they  make  neat  labels  for  each  box  about  4 
cm.  square. 

3.  Let  the  class  determine  the  relative  weights  in 
such  way  as  may  seem  best,  and  each  record  in  his  table. 

4.  Give  out  the  specimens,  as  in  C,  Step  XIV,  being 
sure  that  the  metals  and  labels  agree. 

5.  Determine  the  magnetism  of  all,  and  record.  Now 
give  a  pinch  of  fine  iron  filings  to  each.    Stroke  the  un- 

in  the  shape  of  coin  or  utensils,  as  it  cost  too  much  to  cut  them 
up.    (But  the  vials  broke  too  easily. 

My  wish  has  always  been  to  take  coin  as  far  as  possible, 
and  then  have  round  pieces  of  the  cheaper  metals  punched  the 
same  size  and  thickness ;  and  if  there  were  a  demand  for  such 
pieces,  they  could  be  had  cheaply. 


METALS  STUDIED.  17 

marked  end  of  the  magnet  with  the  piece  of  wrought 
iron  ten  times,  and  then  see  how  many  of  the  filings  it 
will  pick  up.     (A  few.) 

Do  the  same  with  cast  iron.     (Fewer.) 

Same  with  steel.     (Many.) 

Same  with  nickel.     (A  few.) 

Same  with  tin  plate.     (Few.) 

Lay  down  the  magnet,  and  try  the  metals  again  after 
the  little  rest,  and  decide  which  keeps  its  magnetism  best 
after  rubbing  on  a  magnet.     (Steel.) 

Let  each  stroke  the  unmarked  end  of  his  magnet 
with  a  knife  blade  or  large  needle,  in  each  case  hav- 
ing the  point  the  last  to  leave  the  magnet  at  each 
stroke.  These  can  be  suspended  at  home  by  fine 
thread  (away  from  iron).  Which  way  do  they  point  ? 
(North.) 

Why  is  tin  "  plate  "  magnetic  and  tin  not  ?  (It  is 
iron  or  steel  coated  with  tin.) 

6.  Bend,  and  record. 

7.  Pound.  This  may  best  be  done  at  close  of  school. 
Use  "  tack "  hammers  and  any  piece  of  iron  weighing 
half  a  kilogramme  or  so.  Insist  that  it  be  held  on 
the  lap  or  knee  (to  deaden  the  noise). 

8.  Give  streak  tiles  and  record  streaks.  (It  is  a  good 
plan  to  make  the  streaks  in  a  neat  and  orderly  row 
across  the  tile  from  left  to  right.  To  see  them  all  at 
once  is  instructive.) 

9.  Record  color  from  fresh  surface  only.  This  point 
is  very  important. 

10.  Hardness. — Take  a  bit  of  window  glass  first.  Any 
that  scratch  it  in  the  least  are  "  hard."  To  test  the  others^ 
take  a  piece  of  copper  with  a  sharp  corner.  Those  it  will 
not  scratch  are  "medium."  Itself  and  all  it  scratches 
are  called  "  soft." 

This  "scale  of  hardness"  agrees  with  the  tests  of  min- 
erals both  in  Step  VIII  and  Step  XXXVII. 
3 


18  SYSTEMATIC  SCIENCE  TEACHIXG. 

11.  Heat. — Give  three-centimetre  bits  of  candle  (Christ- 
mas tapers  will  do).     Light,  and  have  a  talk  about  the 
structure  of  a  flame.    Place  the  illustrations  from  some 
chemistry  on  the  blackboard  in  colors. 
Note  the  solid  candle ; 

the  cup  of  melted  wax  or  tallow ; 

the  wick,  unburnt  in  the  center  of  the  flame ; 

the  blue  base  of  the  flame ; 

the  dark  center,  extending  a  little  above  the 

wick ; 
the  luminous  cone,  continually  disappearing  in 
the  air  above. 
Lead  the  class  to  see  that  everything  must  be  vapo- 
rized before  it  burns  with  a  flame,  by  talking  of  the 
tongues  of  flame  shooting  up  from  soft-coal  fires,  and  of 
the  jets  which  shoot  and  hiss  from  wood  or  dart  up  the 
chimney. 

In  the  kerosene  lamp  the  liquid  oil  climbs  up  the 
wick  and  is  vaporized  by  the  heat  at  the  top.  In  the 
candle,  how  is  it  ? 

That  the  center  of  the  candle  flame  is  comparatively 
cool  gas,  may  be  shown  by  holding  a  splinter  of  wood 
across  the  flame  a  few  seconds  and  quickly  removing. 
It  will  have  an  unburnt  space  between  two  burnt  ones. 

A  sheet  of  white  paper  pressed  down  on  the  flame 
and  removed  before  it  can  take  fire  shows  a  ring  of 
chari-ed  paper. 

Now,  by  holding  a  bit  of  fine  wire  in  the  flame,  de- 
cide which  part  is  hottest.     (Tip  of  inner  cone.) 

Note. — Whether  the  teacher  will  explain  this  depends  on  tlie 
class.  Unless  he  can  express  himself  in  terms  of  the  child's  ex- 
perience, he  must  not  attempt  it ;  the  observation  is  enough  for 
the  present. 

Where,  then,  shall  we  hold  our  metals  to  try  the  effect 
of  heat  on  them  ? 


METALS  STUDIED.  19 

Try  each  metal  in  as  nearly  the  same  way  as  possible, 
and  record.  Let  the  time  be  one  minute,  unless  melting 
or  burning  takes  place  sooner. 

12.  Place  twenty-two  small  dishes  in  some  safe  but 
easily  accessible  place.  Let  different  pupils  bring  pieces 
of  metal  so  that  twenty  dishes  will  each  have  two  bits  of 
the  twenty  different  metals  in  them.  Pour  on  water, 
and  leave  twenty-four  to  forty-eight  hours. 

The  class  observe  the  results  and  record. 
Dry  and  return  such  of  the  metals  as  are  uninjured. 
Talk  of  the  ways  in  which  this  varying  behavior  affects 
us — pipes,  jewelry,  cooking  utensils,  etc. 

13.  Here  are  two  metals  I  did  not  dare  give  you. 
They  must  be  kept  in  kerosene.  See  !  I  can  easily  cut 
this  sodium  with  a  knife.  Record  its  hardness.  This  po- 
tassium cuts  just  as  easily.  Samuel  may  carry  the  piece 
of  potassium  around  for  all  to  look  at,  and  Annie  the  so- 
dium. No  one  must  touch  the  pieces.  Why  ?  Record 
anything  you  can  about  them. 

Now  observe  as  I  drop  the  potassium  on  water.  (Ploats 
and  takes  fire.)  I  will  try  another  piece  for  you  to  note 
the  color  of  the  flame.  (Violet.)  Now  see  the  sodium. 
(Floats  and  rushes  about,  a  silvery  globule,  till  all  gone.) 

I  will  try  another  piece  on  warm  water.  (Burns 
with  a  yellow  flame.) 

Why  did  I  ask  you  not  to  touch  these  metals  ? 
(Burn  fingers.) 

Now  record,  and  the  lesson  is  done. 

Review. 

14.  John,  name  those  metals  that  are  heavy. 
Mary,  those  that  are  light. 

Samuel,  how  many  are  medium  ? 

Alice,  name  them. 

Do  all  metals  sink  in  water  ?    Which  do  not  ? 

Which  are  magnetic  ? 


20  SYSTEMATIC  SCIENCE  TEACHING. 

Which  one  keeps  its  magnetism  ? 

Is  it  magnetized  now  ? 

How  could  you  make  a  knife  point  north  ? 

Name  those  that  are  brittle. 

Those  that  are  elastic. 

What  do  we  call  the  others  ? 

What  is  a  "  malleable  "  metal  ? 

Name  those  which  are. 

Name  the  brittle  ones. 

What  do  you  understand  by  "  streak  "  ? 

Name  those  giving  metallic  streaks. 

Those  giving  no  streaks. 

Why  did  they  not  mark  the  tile  ? 

Do  any  give  unmetallic  streaks  ? 

Name  the  reddest  metal. 

The  yellowest. 

The  whitest. 

The  bluest. 

How  does  "  brass  "  differ  from  "  gold  "  yellow  ? 

Describe  a  "  bronze  "  color. 

How  does  "  iron  black  "  differ  from  steel  gi'ay  ? 

Would  you  accept  a  dollar  made  of  tin  ? 

How  does  "  tin  white  "  differ  from  "  silver  white  "  ?  * 

How  would  you  find  which  metals  are  hard  ? 

Name  them. 

What  test  for  those  soft  ? 

Name  the  "  medium  "  ones. 

Draw  a  diagram  of  a  candle  fiame  on  the  board. 

Who  can  tell  me  how  a  candle  burns  ? 

Could  there  be  flame  without  gas  ? 

Name  as  many  flames  as  you  can. 

What  is  the  dark  center  ? 

*  (Note  to  Teacher. — The  pupil  should  learn  to  observe  the 
streaks  carefully,  for  on  clear  conceptions  of  metallic  colors 
much  depends  in  the  future  work.) 


11   ^i^jiVERSi 

OF 


METALS  STUDIED.  21 

How  proved  cool  ? 

Where  would  you  hold  something  to  heat  ? 

Name  those  metals  which  burned. 

Those  which  melted. 

Those  which  changed  color. 

Which  became  cleaner  and  brighter  ? 

Which  metals  rusted  ? 

Have  you  seen  any  at  home  which  rusted  ? 

Will  water  put  out  all  flames  ? 

How  can  we  prevent  rusting  ?  (Keep  dry  by  oil, 
paint,  etc.) 

After  a  rapid  and  exhaustive  review  in  this  manner, 
proceed  to  test  the  pupils. 

15.  Sort. — Each  empty  out  his  labels  and  metals  in  a 
pile,  and  then,  taking  the  first  label  he  picks  up,  find  the 
specimen  which  belongs  with  it,  and  return  to  a  tray. 
Then  take  another  label  and  its  metal,  and  so  on  till  done. 

Now  all  are  done.  Change  boxes,  and  if  you  find  an 
error,  raise  your  hand.    When  corrected,  return  boxes. 

16.  Each  put  his  metals  in  a  mixed  pile,  and,  having 
changed  boxes,  sort  a  set  you  had  not  before  seen.  Bring 
to  me  when  done.     (Teacher  keeps  them  when  correct.) 

17.  Putting  away. — Clean,  dry,  and  wrap  up  as  di- 
rected in  Step  III,  and  put  away  in  boxes. 

18.  Beview  from  Memory. — There  is  no  more  eflPective 
way  (for  me)  of  review  than  the  following.  It  keeps  the 
close  attention  of  all,  stimulates  thought  and  memory, 
pleases  the  bright,  and  teaches  the  dull.  "Written  re- 
views "  can  not  compare  with  its  results  as  regards  clear 
and  helpful  knowledge  of  the  subject,  and  I  prefer  to 
defer  "compositions"  to  some  other  time.  Of  course, 
the  language  should,  as  always,  be  terse  and  correct. 

No  child  must  repeat  what  has  been  told. 
Who  will  tell  me  something  about  metals  ? 
Some  one  else  tell  another  thing. 
Another. 


22  SYSTEMATIC  SCIENCE  TEACHING. 

What  more  ? 

No  repeating ;  that  has  been  told. 

What  more  ? 

In  this  way  the  subject  can  be  exhausted,  and  many 
interesting  things  brought  out  of  which  tlie  teacher 
would  not  think.  Some  of  these  will  prove  errors  or 
misconceptions,  and  can  be  set  right,  while  bright  and 
original  ideas  can  be  warmly  recommended. 

This  will  close  an  interesting  and  instructive  set  of 
lessons. 

Next  step,  XXVI— Solid  Form. 


STEP  XXVL— SOLID  FORM. 

Object.— 1.  To  continue  the  work  begun  in  Step  XXI 
(Plane  Form  and  Color). 

2.  To  familiarize  with  some  fundamental  solids  in 
preparation  for  the  study  of  crystals,  minerals,  and  other 
work. 

Time. — In  late  spring,  and  at  such  time  of  the  session 
as  the  pupils  need  a  rest  from  study.  About  twenty  les- 
sons of  thirty  minutes  each.  As  in  work  on  Form,  it  is 
best  to  have  fewer  lessons  and  have  them  longer. 

Material — For  a  class  of  thirty  there  will  be  needed 
thirty  clay  boards,  or  twelve-inch  square  pieces  of  smooth 
thin  board,  well  oiled  on  both  sides  to  prevent  warping, 
fifty  pounds  of  prepared  clay,  such  as  is  used  in  kinder- 
gartens, although  I  do  not  see  why  good  brick  clay 
would  not  do  as  well.  Should  be  in  an  earthen  crock, 
so  as  to  keep  in  good  working  condition. 

Preparations  of  Teacher  will  consist  mainly  in  tak- 
ing some  clay  and  mastering  the  various  pieces  of  work 
before  giving  it  to  the  class.  There  are  books  on  clay 
work  which  would  doubtless  be  helpful,  but  a  study  of 
the  six  systems  of  crystals  in  Dana's  Mineralogy  will 
suggest  what  is  needed,  and  from  those  it  can  be  decided 
which  to  attempt  to  make.  For  those  who  would  sug- 
gest cutting  out  crystal  forms  from  potatoes,  paraflBn, 
soap,  etc.,  I  will  say  that  it  never  worked  in  the  classes 
of  comparatively  young  pupils  I  have  had.  Clay  is 
very  tractable  material,  and  a  little  practice  gives  beau- 
tiful work. 

23 


24  SYSTEMATIC  SCIENCE  TEACHING. 


The  Lessons. 

1.  Give  boards  and  nearly  equal  lumps  of  clay  (size 
of  walnut).    Roll  in  the  palms  till  a  sphere  results. 

Children's  hands  are  so  hot  and  dry  that  if  success 
does  not  soon  come  the  clay  becomes  dry  and  cracks. 
Change  such  lumps  for  fresh  clay.  When  one  ball  is 
made  let  the  pupil  work  at  another,  as  "  practice  makes 
perfect."  Have  a  little  plaque  made  to  place  the  best 
ball  upon,  and  show  how,  by  moistening,  to  stick  the 
two  together.  On  the  plaque  let  the  owner's  name  be 
scratched,  and  set  all  in  one  of  the  trays  used  for  sorting 
and  put  away  to  dry.  It  is  well  for  each  child  to  have  a 
cigar  or  candy  box  for  his  work. 

2.  Oblate  Spheroid. — Give  boards  and  clay  as  before. 
First,  make  a  sphere. 

Second,  flatten  it  a  little  by  unequal  rolling.  No 
plaque  needed. 

3.  Cube. — First,  make  a  sphere. 

Second,  by  constantly  turning  and  gently  dropping 
the  sphere  on  the  board  an  equal  flattening  on  the  six 
sides  will  take  place.  Work  at  it  till  eight  sharp  and 
square  corners  replace  the  rounded  surfaces  of  the  ball. 
Keep  trying  till  it  is  done  well. 

4.  Cone. — First,  make  an  ovoid  (egg-shaped). 
Second,  flatten  the  base  and  roll  alternately  till  a 

cone  results. 

5.  Square  Pyramid.— First,  make  another  cone. 
Second,  by  carefully  dropping  on  opposite  sides  in 

succession  change  the  cone  into  the  pyramid.  Of  course 
the  bottom  must  be  kept  flat,  and  should  be  square. 

6.  Triangular  Pyramid. — First,  make  a  cone. 
Second,  by  flattening  the  sides  in  three  directions  get 

the  triangular  pyramid.  The  bottom  should  be  an  equi- 
lateral triangle.  The  idea  of  threes  may  be  a  little  dif- 
ficult, and  need  illustration. 


SOLID  FORM.  25 

7.  Octahedron. — Fii-st,  make  a  sphere. 

Second,  by  careful  dropping  on  successive  sides 
change  the  sphere  into  a  solid  with  eight  triangular 
faces.  These  triangles  should  be  approximately  equi- 
lateral, and  some  patience  be  needed  to  succeed.  If  the 
sides  should  prove  isosceles,  save  it  to  illustrate  the  di- 
metric  (two-measure)  system  of  crystals. 

8.  Cylinder.— First,  make  a  sphere. 

Second,  by  gently  flattening  the  two  poles  and  rolling 
down  the  equator,  bring  it  to  a  cylinder  with  two  flat 
and  circular  bases. 

9.  Square  Prism.— First,  make  a  cylinder. 

Second,  by  alternate  and  gentle  flattening  change  the 
curved  surface  into  four  equal  rectangles  and  the  cir- 
cular bases  into  squares.  The  eight  corners  should  be 
'*  square  "  and  sharp. 

10.  Rhombic  Prism.— First,  make  a  cylinder. 
Second,  change  this  into  a  prism  whose  sides  shall  be 

rectangles  like  the  square  prism,  but  whose  bases  are 
rhombs.  The  sides  of  the  rhombs  should  be  nearly 
equ^l. 

11.  Triangular  Prism.— First,  make  a  cylinder. 
Second,  working  on  the  principle  of  threes,  change  it 

into  a  triangular  prism,  whose  sides  must  be  rectangles 
and  bases  equilateral  triangles. 

12.  Hexagonal  Prism.— First,  make  a  triangular 
prism. 

Second,  flatten  the  edges  until  you  have  six  rectan- 
gular sides  and  six-sided  ends.  This  prism  can  be  made 
directly  from  the  cylinder,  but  it  requires  a  good  deal  of 
judgment  to  get  the  six  sides  equal  or  very  nearly  so. 

13.  Rectangular  Prism.— First,  make  a  cylinder. 
Second,  by  unequal  flattening  to  adjacent  sides  change 

the  surface  to  rectangles,  but  only  those  opposite  shall 
be  equal,  and  the  bases  shall  be  rectangles.  A  brick  is  a 
good  model. 


26  SYSTEMATIC  SCIENCE  TEACHING. 

So  far  all  angles  between  the  bases  and  sides  (except 
the  pyramids)  have  been  right  angles,  and  all — even  the 
pyramids — have  stood  erect  on  their  base.  All  such 
solids,  prisms,  and  pyramids  are  called  ''right,^^  be- 
cause the  line  from  the  center  of  the  top  to  tlie  center 
of  the  base  (vertical  axis)  is  at  right  angles  with  the 
base. 

14.  Oblique  Prism.— First,  make  a  cylinder. 
Second,  make  a  prism  just  like  the  rectangular  prism, 

except  that  two  of  the  opposite  sides  are  rectangles  and 
two  are  rhomboids,  like  those  of  a  box  crushed  over  to 
one  side.  The  bases  will  still  be  rectangles.  Are  the 
angles  all  right  angles  ?  (Some  obtuse.)  Can  you  make 
an  oblique  prism  on  a  square  base  ? 

15.  Rhombohedron.— First,  make  a  cube. 

Second,  by  careful  dropping  change  the  square  faces 
of  the  cube  into  rhombs.  Can  you  find  any  right  angles 
to  the  faces  ?  To  the  edges  ?  Are  the  corners  "  square 
corners  "  ? 

16.  Original  Designing.— The  rhombohedron  ends  the 
work  I  have  given.  If  you  can  arrange  for  the  class 
to  do  some  original  work  in  clay,  it  will  be  a  good 
thing,  but  do  not  take  school  time  for  it.  If,  as  in 
Plane  Form,  the  chance  to  work  with  clay  in  original 
designs  be  contingent  on  and  follow  the  performance 
of  excellent  work  in  the  ordinary  school  studies,  a 
mild  stimulus,  in  no  wise  hurtful,  will  be  supplied  to 
secure  steady  and  vigorous  work  on  the  studies  for  the 
sake  of  the  time  to  be  used  at  clay.  But  insist  that 
nothing  less  than  excellent  work  shall  gain  the  privi- 
lege. 

17.  Name  Solids. — Let  each  pupil  have  his  fifteen  solids 
before  him,  and  they  will  now  be  hard  and  dry  enough 
to  write  on  each  its  name.  Put  these  in  a  large  printing 
hand  on  the  board,  and  be  sure  each  child  gets  the  right 
name  and  solid  together. 


SOLID  FORM. 


27 


18.  Study  of  Solids. — Let  each  child  make  from  card- 
board (tin  or  brass  would  be  better,  and  cost  but  little) 
a  copy  of  this  device  for  measuring  angles.    Now  let 


90- 


I/O" 


«b« 


150" 


Fig.  5. 


each  have  his  complete  set  of  claywork  in  a  tray,  and 
it  will  be  a  great  help  if  the  wooden  models  of  crystals 
suggested  in  Step  XXXVI  be  also  given,  as  the  angles 
of  the  claywork  will  not  be  very  constant  or  exact.  Now 
draw  the  lines  of  the  following  table  on  the  board  and 
let  the  class  copy,  and,  with  your  help,  study  the  solids 
and  fill  out. 

19.  After  this  measuring  of    angles,   counting    and 
comparing  of  sides  and  edges,  there  only  remains  the 


28 


SYSTEMATIC  SCIENCE  TEACHING. 


SOLID 

PLANE 
ANGLES  OF 

SOLID 
ANGLES 

EDGES 

SHAPE  OF 

AXIAL 

Bases 

Sides 

Basal 

Inter- 
facial 

Number 
and  Length 

Bases 

Sides 

DIMEN- 
SIONS 

Sphere 

0 

0 

0 

0 

0 

1 



— 

* 

All  = 

Cube 

90°=JLS 

90°"LL 

90° 

90" 

12 

All    = 

0 

3 
0 

4 

All   = 

Regular 
Octahedron 



00°  E 

90° 

Nearly 
110" 

& 

70° 

13 

All    = 

8 



As 

All    =^- 

Square 
Prism 

90°  LL 

90°  LI 

90°  11 

90° 

8  Basal  * 
-+-or- 

the 
4  lateral 

6 

2 

0 

t 
0 

2 

lengths 

Hexagonal 
Prism 

Wlo 

90° 

90 

120° 

12  Basal 
4-or- 
6  lateral 

8 

6 

6 

s 

3 

lengths 

Rhombo- 
hedron 



[1 

& 

& 

12 

All  =? 

0 

— 

ZV 

3 

lengths 

Right 

Rhombic 

Prism 

or 
L2. 

90° 

o 

90 

\1 

or 

L£ 

8  Basal 
tor- 
tile 
4  lateral 

0 

3 

Zi7 

4 
s 

3 

lengths 

Right 

90° 

90° 

90° 

90° 

12 
of  three 
lengths 

0 

2 
»   1 

:i 

I    s    1 

3 

Rectangular 

3 

lengths 

Prism 

1    «    1 

Oblique 
Prism 

90° 

or 
12 

liLiLL 
& 

90° 

12 
lengths? 

ti 

2 

1   s  1 

2 

,  5i  , 

3 

lengths 

1  -  1 

Doubly 

Oblique 

Prism 

& 
l£ 

& 
12. 

& 

& 

L2. 

13 

lengths? 

(i 

3 

A/ 

4 

A/ 

3 

lengths 

*     -{-or—  means  more  or  less,  gi*eater  or  smaller  than;  =■  Is  equal,  |r  right  angle; 
\!\  acute  anifle ;  [o^  obtuse  angle 


SOLID  FORM.  29 

task  of  arrang-ing  and  grouping  these  facts  in  the  child's 
mind.    Do  this  by  Questions,  somewhat  as  follows  : 

What  solid  seems  to  include  all  others  ?      (Sphere.) 

Which  solids  have  their  faces  in  sets  of  threes  ? 

Which  their  faces  in  fours  or  eights  ? 

Which  are  '*  right "  (or  erect)  ? 

Which  are  "  oblique  "  on  their  bases  ? 

Which  have  all  their  angles  right  angles  ? 

Which  have  all  their  dimensions  equal  ? 

Which  have  all  faces  equal  and  similar  ? 

Which  have  all  angles  right,  but  their  edges  of  two 
lengths  ? 

Which  have  two  kinds  of  faces  ? 

Are  there  any  having  edges  of  three  different  lengths  ? 

How  about  their  faces  ?    (Three  kinds.) 

Which  has  the  most  faces  ?  What  shape  are  the 
bases  ? 

Which  has  only  one  surface  ? 

Which  has  the  smallest  faces  ?  What  shape  is  the  base  ? 

Which  have  the  faces  all  squares  ?    All  triangles  ? 

Which  have  one  kind  of  rectangle  ?  Two  kinds  of 
rectangles  ? 

Which  have  sides  and  bases  all  rectangles  ? 

Which  have  both  squares  and  rectangles  ? 

Do  "right"  solids  have  any  other  angles  than  90°  ? 
When  ? 

Which  has  three  kinds  of  angles  ? 

Which  has  no  right  angles  ? 

Describe,  in  brief  terms,  a  sphere. 

Describe  an  oblate  spheroid. 

Describe  from  memory  a  cube. 

How  would  I  know  a  tetrahedron  ? 

How  an  octahedron  ? 

Pick  out  your  ovoid  and  tell  me  what  is  peculiar 
about  it. 

What  does  the  word  prism  mean  to  you  ? 


30  SYSTEMATIC  SCIENCE  TEACHING. 

Describe  from  memory  a  triangular  prism. 

Describe  a  square  prism. 

A  hexagonal  prism. 

How  does  a  rectangular  differ  from  a  square  prism  ? 

Describe  an  oblique  prism. 

How  does  a  rhombohedron  differ  from  a  cube  ? 

Question  in  this  way  till  the  solids  are  familiar,  and 
then  the  work  is  complete. 

Review. — Nothing  further  needed. 

Material  put  away. — Give  the  pupils  their  completed 
work.  Put  all  poor  and  broken  clay  work  in  the  jar, 
add  a  little  water,  and,  after  twenty-four  hours'  soaking, 
ram  all  down  smooth  and  cover  the  jar  tightly  in  a 
damp  cellar  till  again  wanted. 

Put  away  all  wooden  models,  etc. 

The  next  step  will  be  XXXI — Molecules. 


STEP  XXVII.— ANIMALS. 
The  Boy  Lessons. — (Concluded.) 

The  Object  of  this  Step.— Through  the  first  three 
years'  work  the  foundation  for  a  wide  acquaintance  with 
animals  was  laid,  and  the  fourth  (Step  XIX)  continued 
this  work  to  the  use  of  organs  and  some  aspects  of  inter- 
nal structure. 

My  experience  has  been  that  there  are  always  more 
or  less  new  members  in  a  class,  and  with  a  view  to  bring- 
ing these  into  line,  of  reviewing  the  past  work,  and  pre- 
paring for  comparison  and  classification,  I  have  used 
the  continuation  of  The  Boy  (Step  XIX).  No  new  ani- 
mals are  introduced,  but  in  connection  with  a  rapid  re- 
view  is  a  new  view  of  certain  types  among  those  pre- 
viously looked  at. 

Time. — In  the  plan  to  introduce  animal  work  at  dif- 
ferent times  of  the  school  year  this  step  falls  in  late 
spring,  say  May  and  June.  Take  it  up  at  such  time  of 
the  day  as  the  pupils  need  relaxation. 

About  fifty  lessons  of  fifteen  minutes  each  will  be 
needed. 

Material. — (For  a  supposed  class  of  thirty.)  I  have 
usually  obtained  this  fresh  each  time,  but  there  are  some 
things  which  can  be  kept  to  advantage. 

1.  A  cow's  horn,  sawed  otf  near  the  root  to  show  the 
bony  axis  (or  better  as  in  2). 

2.  Cow's  Upper  and  Lower  Jaws.— Get  a  cow's  head 
(having  short  and  handsome  horns)  of  the  butcher,  and 
sink  it  in  a  pond  of  water  till  the  flesh  has  rotted  off  and 
been  removed  by  the  water  animals.    Scrub  it  clean,  and 

31 


32  SYSTEMATIC  SCIENCE  TEACHING. 

put  in  some  secure  place  in  the  sun  to  dry  and  bleach. 
Now  saw  one  of  the  horns  around,  that  the  horny  cover- 
ing will  slip  off  and  expose  the  bony  axis,  and  a  very 
useful  specimen  for  the  cabinet  will  result. 

3.  A  Cow's  Foot— If  obtained  and  treated  with  the 
head,  it  can  be  easily  prepared.  The  hoofs  will  come 
off,  but  can  be  fastened  on  in  some  way. 

4.  Large  feathers  from  a  hen's  tail,  to  learn  the  parts 
with.    Get  enough  so  that  each  child  can  have  one. 

5.  Of  the  butcher  obtain  thirty  hens'  feet,  cut  off 
where  the  feathers  stop.  Wash  these  thoroughly,  spread 
the  toes  on  a  piece  of  board,  secure  in  position  with  pins, 
and  place  over  a  furnace  or  somewhere  so  that  they  will 
quickly  dry.  I  have  had  a  similar  collection  for  ten 
years,  and  they  have  kept  perfectly  and  been  very  useful, 
although  the  fresh  ones  are  better. 

6.  Have  several  well-dried  wings.  Spread  before 
drying. 

7.  Have  several  good-sized  snakes  in  separate  bottles 
of  alcohoL  Let  the  bottles  be  of  clear  glass,  and  use 
sound,  solid  corks  well  rubbed  with  vaseline  to  prevent 
the  loss  of  alcohol. 

8.  A  cast-off  snake  skin. 

9.  A  handful  of  the  ctenoid  scales  of  the  biggest  perch 
or  wall-eyed  pike  to  be  obtained.    Wash  well,  and  dry. 

Preparation  of  the  Teacher.— This  should  include  a 
careful  study  of  the  object  to  be  reached,  of  the  material 
available,  and  the  pupils  to  be  instructed. 

Having  modified  this  plan  as  may  seem  best,  and  de- 
cided what  species  of  animals  are  most  available,  proceed 
to  go  through  the  lessons  (as  outlined)  with  the  animal 
before  you,  and  make  such  changes  or  additions  as  may 
seem  best  under  the  existing  conditions  of  locality,  pu- 
pils, etc. 

Then  only  would  I  advise  a  teacher  to  attempt  to  give 
the  work,  as  otherwise  he  will  have  so  little  of  free- 


ANIMALS.  33 

clom  for,  and  so  little  life  in  its  presentation,  as  to  make 
the  lessons  very  uninteresting  to  all  concerned. 

The  Lessons. 
An  outline  of  the  work  of  this  step  will  be  the  study  of 
a  descending  series  of  types,  from  the  cow  to  the  sponge. 
This  work  is  to  be  a  review  of  the  past  lessons,  an  appli- 
cation of  the  study  of  The  Boy,  and  an  introduction  to 
the  grouping  of  animals  to  come  later.  Push  the  work 
energetically ;  but  in  this  always  guard  against  a  few 
bright  pupils'  doing  all  the  talking,  and  by  individual 
questions,  etc.,  draw  out  the  timid  and  less  ready  ones. 
I  have  covered  the  ground  easily  in  eight  weeks'  work 
of  fifteen-minute  lessons,  but  my  class  was  smaller  than 
most  teachers  will  have,  and  I  had  other  advantages  to 
aid  me  which  those,  especially  beginners,  will  lack.  As 
experience  is  gained,  the  time  will  lessen  without  danger 
of  overfeeding  the  pupil. 

The  Cow.'' 

1.  Parts. — (Have  a  picture  or  the  animal  before  the 
class.) 

Head,  legs,  body,  tail,  and  udder. 

2.  Body.— Its  shape  ? 
Warm,  or  cold  ? 

What  is  the  whole  body  covered  with  ? 

3.  Skin.— Color  ?    Feeling  ?    (Soft  and  thin.) 
How  does  it  fit  ? 

What  is  the  skin  mostly  covered  with  ? 

4.  Hair.— Where  ? 

Color  ?    Shape  ?     (Straight  or  curly.) 

Size  ?     (Long,  short,  fine,  coarse.) 

Which  way  does  it  run  ?    Why  ?     (Shed  rain,  etc.) 

Uses  ?  t 

*  A  good  one  for  milk  and  butter  is  in  mind. 

f  "  Use  "  always  is  to  be  understood  as  to  the  animal. 


34  SYSTEMATIC  SCIENCE  TEACHING. 

Is  there  anything  else  on  the  skin  but  hair  ? 

5.  Hoofs. — Where  ?    (Covering  ends  of  toes.) 
Color  ?    Shape  ? 

Can  a  cow  move  the  hoof  without  moving  the  whole 
toe? 

How  many  ?  (Four  on  each  foot.)  Are  these  alike 
in  size  ? 

Which  way  are  the  larger  ones  directed  ? 

Of  what  use  are  these  ?     (Protect  the  toes.) 

Of  what  use  are  the  small  hinder  toes  ? 

What  do  the  lines  on  the  hoof  suggest  as  to  their 
structure  ?    (Matted  hail's.) 

What  other  animals  with  cleft  hoofs  do  you  know  of  ? 

Any  other  covering  besides  hair  and  hoofs  ? 

6.  Horns.— Where  placed  ? 

Color  ?    Shape  ?    (Conical.)    How  many  ? 

Which  way  do  they  point  ? 

Do  they  ever  come  off  naturally  ?     (Not  shed.) 

What  can  you  observe  on  the  surface  ?  (Parallel 
lines.) 

Examine  the  young  sprouting  horn  of  a  calf  and  find 
the  cause  of  these  lines. 

Are  they  hollow,  or  solid  ?    (Hollow  caps  to  the  bone.) 

Of  what  use  are  they  ?    (Defense.) 

What  other  animals  have  hollow  horns  ? 

How  many  things  grow  from  the  skin  ?  (Hair,  hoofs, 
and  horns.) 

Where  are  the  horns  ?     (On  the .) 

7.  Head.— Its  shape  ? 

What  motions  ?     (Very  varied.) 
What  parts  ?    (Ears,  eyes,  nostrils,  and  mouth.) 
What  connects  it  to   the   body  ?    (Neck.)    Why   is 
this  long  ?    (To  reach ?) 

8.  Ears.— Where  ?    How  many  ? 
Shape  ?    Motions  ?    Directed  ? 
Use  ?    (To  hear.) 


ANIMALS.  35 

9.  Eyes. — Where  placed  ?    Deeply  set,  or  prominent  ? 
Directed  ?    (Sidewise.) 

Why  thus  placed  ?  (Consider  the  habits  in  feeding, 
and  the  dangers,  in  the  wild  state,  exposed  to.)  How 
many  ? 

Shape  ?  Size  ?  (Not  very  large  for  the  size  of  the 
animal.) 

Use  ?    (To  see  food,  danger,  etc.) 

Parts  ?    (Lids,  ball,  and  tear.) 

10.  Lids. — How  many  ?    Move  which  way  ? 
Use  ?    Use  of  lashes  ?    Use  of  tear  ? 

11.  Ball— Shape  ?    Motions  ?    Color  ? 
Shape  of  pupil  ?    {Transversely  oval.) 

12.  Nostrils.— Where  ?    Shape  of  opening  ?    Directed  ? 
Motion  ?    Use  ?    (Breathe  and  smell.) 

What  is  there  to  notice  about  the  skin  of  the  nose  ? 
(Moist  and  bare.) 

How  does  a  cow's  breath  smell  ?    (Fragrant.) 

13.  Mouth, — Where  ?  An  up  -  and  -  down,  or  cross 
slit? 

Use  ?    Parts  ?    (Lips,  teeth,  tongue,  and  saliva.) 

14.  Lips. — Thick,  or  thin  ?  Are  they  sensitive  to 
touch  ?    (Very.) 

Why  bare  of  hair  ?    (Constant  wear.) 
Use  ?    (Seize  and  hold   food,  to  aid  in  chewing,  to 
drink,  etc.) 

15.  Teeth.— Where  ?    How  arranged  ? 

What  remarkable  thing  about  the  upper  set  ?  {No 
front  teeth.) 

Kinds  ?    How  many  of  each  ?    (  i.  «— 51    c.  - — -,    pm. 

3-3  3-3      „„  \ 

3:^,™.  3-3  =  32.) 

What  do  the  front  teeth  bite  against  ?    (Elastic  pad.) 
What  motion  does  a  cow  give  to  her  head  in  biting 
off  a  mouthful  of  grass  ? 


36  SYSTEMATIC   SCIENCE  TEACHING. 

How  do  the  molars  differ  from  ours  ?  (Enamel  is  in 
sheets,  with  a  cement  between.) 

Draw  on  the  board  the  figures  this  enamel  makes  on 
the  tooth's  surface. 

Test  with  knife  or  file,  and  determine  which  is  hard- 
est— enamel  or  cement. 

Of  what  use  can  this  curious  alternating  of  hard  plates 
of  enamel  and  softer  cement  be  ?  (Cement  wears  away 
and  leaves  sharp,  cutting  edges  to  grind  up  the  coarse 
food.) 

Do  you  know  of  other  animals  with  no  upper  biting 
teeth? 

See  if  you  can  find  others  having  figures  of  enamel 
among  softer  cement.    (See  collection.) 

16.  Tongue.— Where  ?    How  fastened  ?    (Back  end.) 
Shape  ?    Surface  ?    Tip  ? 

Use  ?  (Draw  in  food,  move  it  about  in  the  mouth, 
and  keep  it  between  the  teeth  for  grinding.) 

17.  Saliva.— Should  you  think  a  cow,  eating  hay  or 
grass,  would  need  much,  or  little,  saliva  ?    (Much.) 

Teacher  tell  of  huge  glands  covering  much  of  the  side 
of  the  face  below  the  ear. 

Of  what  use  is  the  saliva  ?  (Moisten,  soften,  and 
change  food.) 

When  lying  down  and  resting,  what  motion  do  cows 
generally  make  ?  (Chewing.)  What  do  they  chew  when 
not  eating  ?    (Cud.) 

What  is  the  "  cud "  ?  (A  bunch  of  hastily  swal- 
lowed food,  which,  having  been  softened  in  a  peculiar 
stomach,  is  brought  up  again  to  be  thoroughly  chewed.) 

Do  you  know  other  cud  chewers  ? 

18.  What  does  the  cow  walk  with  ? 

Legs.— How  many  ?    How  arranged  ?    (Two  pairs.) 
What  are  four-legged  animals  called  ?    (Quadrupeds.) 
Are  these  pairs  of  legs  equally  strong  ?    (No ;  hind 
legs  strongest.) 


ANIMALS.  37 

What  keeps  them  stiff  and  firm  ?  (Bones.)  Are  they 
hollow,  or  solid  ? 

What  fills  the  hollow  in  the  larger  bone  ?  (A  fatty 
substance  called  marrow.) 

Where  are  a  cow's  bones  ?    ( Under  skin  and  flesh.) 

Have  they  joints  ?  We  call  such  "  an  internal,  bony, 
jointed  skeleton." 

Do  you  know  other  animals  with  internal,  bony,  and 
jointed  skeletons  ? 

What  kind  of  joints  at  hip  ?    At  shoulder  ? 

Remembering  (Step  XIX)  that  elbows  and  heels  point 
back,  and  knees  and  wrists  forward,  point  out  a  cow's  el- 
bow.   Heel.    Wrist.    Knee. 

Why  do  so  many  people  take  the  wrist  for  the  elbow 
and  the  heel  for  the  knee  ?  (Because  the  shoulder  and 
hip  joints  are  hidden.) 

What,  strictly  speaking,  does  a  cow  walk  on  ?  (Ends 
of  fingers  and  toes.) 

What  do  we  call  the  ends  of  her  legs  ? 

19.  Feet. — How  many  feet  ?  How  many  toes  on 
each  ? 

How  many  toes  does  she  walk  on  ? 
What  is  such  a  two-toed  hoof  called  ?    (Cloven.) 
Do  you  know  other  cloven-footed  animals  ? 
What  causes  the  rattling  noise  when  a  cow  runs  ? 
(Toes  strike  together.) 

20.  Review.— What  parts  have  we  studied  ? 
Skin,  with  its  hair,  hoofs,  and  horns. 
Head,  with  its  ears,  eyes,  nose,  and  mouth. 
Eyes,  with  their  lids,  balls,  and  tear. 
Mouth,  with  its  lips,  teeth,  tongue,  and  saliva. 
Legs,  with  their  inside,  jointed  bones. 

What  other  parts  to  study  ?     (Tail  and  udder.) 

21.  The  Taa— Where  ?  Its  shape  ?  Length  ?  Mo- 
tions ? 

Uses  ?    (Brush  off  flies.) 


38  SYSTEMATIC  SCIENCE  TEACHING. 

22.  The  Udder. — This  is  a  group  of  huge  glands  to 
separate  milk  from  the  blood.  Is  it  not  truly  wonderful 
that  white  milk  can  be  formed  from  red  blood,  and  so 
much  of  it  each  day  !  How  much  milk  will  a  good  cow 
give  ? 

Has  her  food  anything  to  do  with  it  ? 

Yes,  a  cow  is  really  a  milk-making  machine.    If  you 

supply  a  good  cow  with  plenty  of  proper  food  you  are 

sure  of  plenty  of  milk. 

What  is  the  shape  of  a  good  udder  ?    (Should  run  well 

forward  rather  than  deep.) 

How  many  teats  has  a  cow  ?    (Four.) 
What  are  these  for  ?    (The  calf  to  suck.) 
Do  you  know  other  milk-giving  animals  ? 

23.  Where  does  a  cow  live  ?    (On  land.) 

24.  What  is  her  home  called  ?    (Stable  or  barn.) 

25.  How  does  she  move  ?     (Walks  or  runs.) 
In  what  position  ?     (Horizontal.) 

What  keeps  her  back  straight  ? 

26.  Backbone.— What  is  this  ?  (A  row  of  bones  strong- 
ly joined  to  each  other,  and  extending  from  the  head  to 
the  end  of  the  tail.) 

Do  you  know  of  other  backboned  animals  ? 

27.  How  does  a  cow  sleep  ?  (Lying  down,  with  head 
resting  on  her  side.) 

28.  What  does  she  eat  ?     (Vegetable  food.) 

How  does  she  get  the  food  into  her  mouth  ?  (Tongue 
and  lips.) 

29.  Does  she  need  anything  besides  vegetable  food  ? 
(Air  and  water.) 

30.  Can  she  talk  ? 

How  does  she  let  us  know  that  she  wants  food  ?  (Ac- 
tions and  lowing.) 

When  she  wants  her  calf  ? 

When  angry,  excited,  or  in  pain  ?     (Bellow.) 

31.  What  is  the  young  of  a  cow  called  ?    (Calf.) 


ANIMALS.  39 

What  sounds  does  he  make  ? 

Does  he  resemble  his  mother  ?     (Yes.) 

What  does  he  live  on  ?    (Milk.) 

32.  Of  what  use  is  the  cow  to  us  ?    (Milk  and  flesh.) 

What  kind  of  a  food  must  milk  be,  to  be  able  to  sup- 
ply all  the  wants  of  a  growing  calf  ?    (Perfect  food.) 

What  does  milk  contain  ?  Fat  (butter),  sugar,  casein 
(cheese),  and  water. 

Which  of  these  are  heating  f 

Which  is  able  to  build  muscle  and  nerve  ? 

The  Hen. 

1.  Parts. — (Have  a  hen  or  good  picture  of  one.) 
Head,  body,  legs,  wings,  and  tail. 

2.  Body.— Shape  ?    (Egg-shaped.) 
What  is  the  body  covered  with  ? 

3.  Feathers.— What  do  they  grow  from  ?    (Skin.) 
Are  they  arranged  orderly,  or  scattered  ?    (See  picked 

body.) 

Parts  of  a  feather.  (Give  each  pupil  a  large  one.) 
(Quill,  shaft,  and  vane.) 

What  can  you  say  of  the  quill  ?  (Transparent,  hol- 
low cylinder,  stiff  and  very  light.) 

Of  the  shaft  ?  (Opaque,  angular,  solid,  and  tapering 
to  the  end.) 

Of  the  vane  ?  (Many  little  plates  with  fringed  edges 
which  interlock  and  make  the  feather  resist  the  passage 
of  air.)    Will  they  relock  if  gently  pulled  apart  ?     (Try.) 

Do  all  these  plates  lock  together  ?  (No,  the  soft  lower 
ones  do  not.) 

These  are  called  "  down."  What  use  for  down  ? 
(Warmth.) 

When  our  clothing  wears  out  we  get  new  clothes. 

Did  you  ever  see  a  hen  who  needed  a  new  dress  ? 

How  did  she  look  ? 

How  does  she  get  rid  of  the  old  suit  ?     (Molts.) 


40  SYSTEMATIC  SCIENCE  TEACHING. 

What  do  we  call  the  young  feathers  ?  ("  Pin " 
feathers.) 

Why  does  the  cook  "  singe  "  a  plucked  hen  ?  (Hair- 
like feathers.) 

What  do  we  call  the  large  feathers  of  wings  and  tail  ? 
(Quills.) 

Now  name  as  many  kinds  of  feathers  as  you  can. 

Is  all  the  body  covered  with  feathers  ?  (Comb,  wat- 
tles, bill,  and  legs.) 

4.  Legs.— Where  are  the  legs  ?  (Under  the  middle  of 
body.) 

How  many  ?  (Two.)  Are  they  stiff  f  What  makes 
them  so  ? 

Are  the  hones  jointed  f  Where  are  the  bones  ?  (Un- 
der skin  and  flesh.) 

What  kind  of  a  skeleton  has  a  hen  ?  (Internal,  bony, 
and  jointed.) 

What  have  you  ever  observed  of  the  bones  of  birds  ? 
(White  and  hollow.) 

What  is  the  hollow  filled  with  ?     (Air.) 

(Show  a  plucked  bird.) 

Which  way  do  heels  bend  ?  (Backward.)  And 
knees  ?    (Forward.) 

Now  look  carefully,  and  tell  me  what  the  "legs" 
every  one  speaks  of  really  are  !     (Feet !) 

What  is  the  "  drumstick  "  ?    (Leg.) 

Below  the  leg  is ?     (The  foot.)     This  upright  part 

is  the  tarsus. 

What  does  a  bird  walk  on  ?  (Its  toes.)  As  a  cow  ? 
(No  ;  on  the  whole  toe.) 

What  is  the  tarsus  covered  with  ?  (Scales.)  Do  they 
overlap  ? 

5.  Toes.* — How  many  has  the  hen  ?    (Four.) 

How  are  these  arranged  ?  (Three  in  front  and  one 
behind.) 

*  Have  specimens  for  pupils. 


ANIMALS.  41 

The  hind  toe  is  the  "  first,"  the  inner  toe  "  second," 
middle  toe  "  third,"  and  outer  toe  "  fourth." 

Which  toe  is  directed  backward  ?     (First.) 

Which  forward  ?  (Second,  third,  and  fourth.)  Which 
is  the  shortest  toe  ? 

How  many  small  bones  in  the  first  ?  (Two.)  In  the 
second?  (Three.)  In  the  third?  (Four.)  In  the 
fourth  ?     (Five.) 

What  are  the  toes  covered  with  ?  (Scales.)  How  do 
the  scales  look  and  feel  ? 

Each  toe  ends  in ?     (A  nail.) 

Are  these  nails  retractile,  like  a  cat's  ?    (No.) 

Of  what  use  are  they  ?     (Scratch  up  food.) 

Are  her  toes  webbed  ?  Are  they  all  on  the  same 
level  ?    (Hind  toe  highest.) 

Look  on  the  cut  end  of  your  specimens  (if  fresh)  for 
the  silvery  white  tendons.  Get  hold  of  these  and  pull. 
(Work  the  toes.) 

Where  is  the  muscle  which  works  our  toes  ?  (In  the 
leg.) 

Where  is  the  muscle  to  work  the  hen's  toes  ?  (In  her 
leg  or  "  drumstick.") 

When  she  raises  her  foot  in  walking",  what  happens 
to  the  toes  ?    (Bend.) 

What  happens  to  her  toes  when  her  legs  bend  ? 
(Clasped  together.) 

Of  what  use  is  this  to  the  hen  ?  (Clasps  the  perch, 
even  when  asleep.) 

What  uses  for  legs  and  feet  ?  (Scratch,  walk,  perch, 
etc.) 

Is  there  any  other  way  that  she  can  move  ?  (Fly.) 
With  what  ? 

6.  "Wings. — Where  are  the  wings  attached  ?  How 
many  ? 

What  are  they  covered  with  ?  How  are  the  feathers 
arranged  ? 


42  SYSTEMATIC  SCIENCE  TEACHING. 

What  shape  below  ?  (Concave.)  Above  ?  (Con- 
vex.) 

What  general  shape  or  outline  ?    What  motion  ? 

Which  edge  is  stiffest  ? 

As  the  wing  is  moved  down  what  must  happen  ? 
(Bird  moves  or  air  escapes.) 

Will  it  escape  over  the  front  edge,  or  hind  edge  ? 
(Hind.) 

What  motion  will  this  give  the  bird  ?  (Push  for- 
ward.) 

What  muscles  move  the  wings  ?    (Breast.) 

Does  a  hen  fly  often  ?    (No.) 

What  color  is  the  meat  of  the  breast  ?    (White.) 

What  color  is  the  meat  of  the  legs  ?    (Dark.) 

Who  can  think  of  the  reason  ?    (Legs  used  most.) 

What  does  a  hen  do  with  her  wings  when  not  in  use  ? 
(Folds  them  by  her  sides.)  Do  they  then  reach  beyond 
her  tail  ? 

7.  Tail— Where  ?  Composed  of  what  ?  (Large,  stitf 
feathers.) 

How  many  quills  in  her  tail  ? 
What  motion  can  she  give  these  ? 

8.  Oil  Glands. — Look  on  a  plucked  fowl  for  two  bean- 
like bodies  on  the  back,  at  the  root  of  the  tail.  Press  one 
of  these.  What  comes  from  it  ?  (Oil.)  The  hen  has 
her  oiling  apparatus  all  in  one  place.  How  does  she 
manage  to  get  it  on  her  feathers  ?  We  shall  see  as  we 
study  the 

9.  Head.— Where?    (On  end  of  neck.) 

General  shape  ?  Can  a  hen  turn  her  head  straight 
back? 

Parts.     (Comb,  wattles,  eyes,  ears,  and  bill.) 

10.  Comb.— Where  ?  Shape?  Color?  Is  it  always 
equally  bright  ?  (Brightest  when  laying,  or  facing  dan- 
ger.) 

Can  you  think  of  any  use  the  comb  is  to  a  hen  ?    (Or- 


ANIMALS.  43 

namental,  and  perhaps  to  awe  an  enemy  by  its  vivid 
color.) 

11.  Wattles.— Where  ?  Shape  ?  Color  ?  Use  ?  (Same 
as  comb.) 

12.  Eyes.— Where  ?  (Sides  of  head.)  Does  a  hen 
usually  see  a  worm  with  both  eyes  at  once  ? 

Are  they  deeply  set  ? 

Are  they  large,  or  small,  for  the  size  of  the  animal  ? 
(Large.)  * 

Parts  ?     (Lids,  ball,  and  tear.) 

How  many  lids  ?  f  (Three.)  Which  way  does  the 
third  lid  move  ?     (Across.) 

How  many  times  a  minute  does  she  wink  ?     (Count.) 

What  is  the  shape  of  the  ball  ?    Of  the  pupil  ? 

Can  she  turn  her  eyeballs  ?  Do  both  move  together 
like  ours  ? 

Of  what  use  are  the  eyeballs  ?    (See  with.) 

And  the  lids  ?     (Protect  and  moisten  the  ball.) 

Can  birds  see  well  f  (Have  remarkable,  almost  tele- 
scopic sight.) 

13.  Ears. — Has  the  hen  any  external  ears  ? 

What  indicates  where  they  are  ?  (Circle  of  feathers 
and  hole.) 

Where  are  these  holes  located  ?    How  many  ? 

Use  ?     (To  hear  with.) 

Have  clean  heads  for  the  class  to  examine 

14.  Mouth.— What  do  you  call  a  bird's  mouth  ?     (Bill.) 
Which  way  does  it  open  ?     (Up  and  down.) 

What  is  the  bill  made  of  ?     (Horny  matter.) 
Its  shape  ?     (Somewhat  conical.)     How  many  parts  to 
it  ?     (Two.) 

*  rsir  of  the  entire  hen  in  one  I  measured,  while  a  150-pound 
man's  would  be  less  than  -oVo"- 

f  Gently  touch  a  hen's  eye  with  a  feather  till  she  moves  this 
third  lid. 


44  SYSTEMATIC  SCIENCE  TEACHING. 

The  upper  outline  or  "bridge"  is  called  the  culmen. 

Is  the  culmen  of  a  hen's  bill  straight  ?     (Curved.) 

Is  the  gape  (opening)  straight,  or  curved  ? 

Does  the  gape  or  opening  extend  to  below  the  eye  ? 

Are  the  edges  of  the  bill  notched  ?  (No.)  Are  they 
sharp  ? 

Which  half  shuts  inside  the  other  ?    (Lower.) 

"W  hich  is  greatest,  the  depth  or  the  width  of  the  bill  ? 
(Depth.) 

Such  a  bill  as  the  hen's  is  said  to  be  "short  and  stout." 

What  is  the  bill  for  ?     (Pick  up  food.) 

Does  she  chew  the  food  ?  Examine  the  tongue  and 
see  if  it  is  adapted  for  tasting.     (No.) 

How  does  a  hen  select  her  food  ?    (Sight.) 

15.  Nostrils.— Where  are  these  ?    (At  base  of  bill.) 
What  covers  them  ?     (A  fleshy  scale.) 

Of  what  use  are  they  ?     (Mainly  to  breathe  through.) 

16.  Neck. — What  is  most  noticeable  about  a  bird's 
neck  ?     (Length  and  flexibility.) 

Why  is  it  so  long  and  flexible  ?  (So  that  the  bird  can 
reach  food,  and  all  parts  of  its  body  to  preen  and  oil  its 
feathers.) 

17.  Is  a  hen  a  land,  or  water,  bird  ? 

18.  How  does  she  move  ?     (Walks,  runs,  flies,  etc.) 
How  is  the  body  held  in  walking  ?    Running  ?     (More 

forward.) 

In  flying  ?    How  in  sleeping  ?     (Head  under  wing.) 

19.  What  kind  of  food  does  she  eat  ?     (Miscellaneous.) 
How  is  the  food  taken  ?     (With  the  bill.) 

How  is  the  food  ground  up  and  prepared  ?  (Show  a 
"  crop  ''  with  its  softened  contents,  and  open  a  gizzard  and 
show  its  thick  muscular  walls,  and  gravel  to  grind  up  the 
food.) 

20.  What  does  she  drink? 

How  ?  (Water  in  bill,  and  then  throws  the  head  uji 
for  water  to  run  down.) 


ANIMALS.  45 

Why  does  she  not  drink  as  we  do  ?     (No  fleshy  lips.) 

21.  What  does  she  breathe  ?  (Air.)  What  with  ? 
(Lungs.) 

Yes,  and  these  are  connected  with  the  hollow  bones, 
so  that  it  is  said  *  a  bird  can  breathe  through  a  broken 
bone  when  the  windpipe  is  closed. 

How  many  times  does*she  breathe  a  minute  ?    (Count.) 

How  does  this  rapid  breathing  affect  the  heat  of  the 
body  ?    {Hot) 

Of  what  color  is  the  blood  ?     (Red.) 

22.  What  is  her  home  called  ?     (Nest.) 
Where  made  ?    Of  what  material  ?    What  for  ? 

23.  Eggs. t— Color  ?     Shape  ?     (Typical.)     Surface  ? 
Parts  ?    (Shell,  white,  and  yolk.) 

What  can  you  say  of  the  shell  ?  (White,  hard, 
brittle.) 

Drop  a  bit  of  shell  in  hydrochloric  acid.  (Effer- 
vesces !) 

Place  a  small  o^gg  in  a  tumbler  of  water  and  add  a 
few  c.  c.  of  acid.  In  a  day  or  two  the  lime  will  be  re- 
moved and  the  "soft-shelled"  ^gg  can  be  got  through 
the  neck  of  a  bottle,  or  other  "  impossible  "  place  to  get  an 
Ggg  through  "  without  breaking  it." 

What  else  have  you  learned  ?  (Shell  is  a  tough  skin 
with  lime  in  it.) 

Hold  some  bits  of  shell  up  to  the  light.     (Porous.) 

What  lines  the  shell  ?     (Two  skins.) 

When  you  open  a  hard-boiled  egg  what  do  you  no- 
tice at  the  large  end  ?  (Hollow  place.)  This  is  filled 
with ?    (Air.) 

Does  the  hard  yolk  seem  in  the  middle  of  the  white  ? 
(Nearer  one  side.) 

Mark  "  Up  "  on  one  side  of  an  egg  and  boil  it  in  ex- 

*  Owen,  p.  118. 

f  See  Owen's  Comparative  Zoology,  pp.  193-204. 


46  SYSTEMATIC  SCIENCE  TEACHING. 

actly  that  position.  Where  is  the  white  thinnest  ?  (Up- 
per side.) 

Who  has  seen  a  dish  of  eggs  broken  for  cake  ?  Do 
the  yolks  float  ? 

Do  they  keep  any  particular  position  ?  ("  White  spot " 
side  up.) 

All  of  these  things  are  of  importance  to  this  wonder- 
ful thing  called  an  egg ! 

How  are  a  hen's  eggs  laid  ?    (One  at  a  time.) 

How  many  does  she  lay  ?  (If  left  to  herself,  as  many 
as  she  can  cover.) 

24.  Setting. — What  change  in  the  habits  of  the  hen  ? 
(Stops  laying,  sets,  etc.) 

Does  she  feed  ?    Drink  ?    Dust  ?     (Same  as  ever,  but 

hurriedly.) 

Why  does  she  hasten  back  ?  (Eggs  must  not  get  cold.) 
How  long  must  she  continue  to  set?  (Twenty-one  days.) 
How  is  she  protected  from  enemies  while  on  the  nest  ? 

(Colors.) 

What  traits  of  character  does  she  display  ?    (Patience 

and  courage.) 

After  the  twenty-one  days  are  passed,  from  the  eggs 

come  what  ? 

25.  Chickens.— How  do  these  get  out  of  the  shell  ? 
(Pick  an  opening.) 

How  are  they  clothed  ?  (Down.)  Do  they  resemble 
the  hen  ?     (Yes.) 

Can  they  soon  run  about  ?    And  pick  up  food  ? 

What  do  they  eat  ? 

How  do  they  call  the  hen  ?    ("  Peep,  peep ! ") 

Where  do  they  sleep  ?  What  does  the  hen  do  at  such 
times  ?  (Gathers  them  under  her  wings  and  quiets  them 
by  "  crooning.") 

What  is  the  use  of  so  much  food  in  the  egg  ?  (To  feed 
the  growing  chick  so  that  it  may  be  able  to  run  about 
and  feed  itself  when  hatched.) 


ANIMALS.  47 

26.  How  does  the  hen  call  her  brood  ?  ("  Cluck, 
cluck!") 

What  sounds  when  she  has  food  ?     (Chuckle.) 
When  danger  threatens  ?     (Warning  cry.) 
When  hurt  herself  ?     (Squawks.) 
When  an  egg  has  been  laid  ?     (Cackles.) 

The  Snake* 

Have  several  medium-sized  snakes  in  clean  fruit  jars 
to  pass  around  ;  also,  as  the  class  gains  courage,  have  one 
or  two  to  pass  about  from  hand  to  hand. 

1.  Parts?— (Head,  body,  and  tail.) 

2.  Head. — Shape  ?  (Note  the  graceful  taper  in  our 
harmless  snakes.)  Motions  ?  Covered  with  ?  (Broad 
scales.) 

Parts  ?     (Eyes,  nostrils,  and  mouth.) 

3.  Eyes. — Where  placed  ?  (Note  how  high  up  on  the 
sides  of  the  head.) 

How  many  ?  Shape  of  ball  ?  Pupil  ?  (Usually  round 
in  harmless  snakes.) 

Size  ?    Motion  ?    Use  ? 
Are  there  any  lids  ? 

4.  Nostrils.— Where  placed  ?    How  many  ? 

Shape  ?  Directed  ?  Use  ?  (Snakes  seem  to  have  an 
acute  sense  of  smell.) 

5.  Mouth. — Where  ?    An  up  and  down  or  a  cross  slit  ? 
Motion  ?    Use  ?     (To  take  food.) 

Who  has  ever  seen  a  snake  swallowing  anything? 
Tell  us  about  it. 

How  do  yoai  suppose  it  could  get  such  a  big  thing  in 
its  small  mouth  ?  (Bones  of  head  are  loosely  connected 
by  gristle,  and  can  expand  and  stretch  enormously.) 

Parts  of  mouth  ?     (Lips,  teeth,  tongue,  and  saliva.) 

6.  Lips.- What  about  these  ?     (Thin  and  delicate.) 

*  Any  common,  harmless  kind. 


48  SYSTEMATIC  SCIENCE  TEACHING. 

7.  Tongue.— Where  fastened  ?     (Behind.) 

What  can  you  say  of  it  ?  (Slender,  forked,  and  dark- 
colored.) 

Can  the  snake  put  it  out  when  the  mouth  is  shut  f 
Use  ?     (To  spread  the  saliva  on  its  food  before  swal- 
lowing and  as  a  means  of  defense,  the  rapidly  darting- 
tongue  adding  much  to  the  threatening  appearance  of 
the  animal.) 

8.  Teeth.— Where  ?     (Feel  with  a  pencil  point.) 
How  arranged  ?     (In  a  single  row  around  the  jaws.) 
Shape  ?     (Points,  curved  backward.) 

Use  ?  (To  hold  food  and  aid  in  swallowing  live 
prey.) 

9.  Saliva. — Is  this  abundant  ? 

Why  needed  ?     (To  lubricate  the  food  in  swallowing.) 

10.  Ears.— Can  you  see  any  ? 

Do  snakes  seem  to  have  good  hearing  ?    (No.) 

11.  Body. — Shape  ?  What  can  you  say  of  the  legs  ? 
(None !) 

Is  it  stiff  or  flexible  ? 
What  is  it  covered  with  ? 

12.  Skin.— Is  the  skin  loose  or  tight  ? 
What  is  the  skin  covered  with  ? 

13.  Scales. — How  arranged  ?     (In  regular  rows.)* 
Colors.     (Note  the  way  these  are  arranged  to  harmo- 
nize with  the  snake's  surroundings,  and  so  protect  it.) 

What  shape  are  the  scales  ? 

Has  each  one  a  ridge  through  the  middle,  or  is  it 
smooth  ? 

How  many  rows,  counting  over  the  bapk  ? 

How  about  the  scales  on  the  belly  ?  (Large  and 
broad.) 

Do  the  scales  ever  get  worn  and  need  renewing  ? 

How  is  it  done  ?  (A  new  set  of  scales  grows  under  the 
old,  which  then  become  loose,  split  away  at  the  mouth, 
and  the  snake,  by  getting  in  some  close  bushes  or  coiling 


ANIMALS.  49 

among  grass,  strips  off  the  old  skin  (slough),  turning  it 
inside  out.) 

14.  Tail. — (Simply  a  continuation  of  the  cylindrical 
body.) 

15.  Where  does  this  snake  live  ?    (Depends  on ?) 

16.  How  does  it  move?  (Let  it  crawl  through  the 
hands,  so  as  to  feel  the  play  of  the  ribs  which,  like  many 
feet,  urge  it  on.  Snakes  mainly  move  by  curving  the 
body  and  pushing  with  the  curves.  They  make  very 
little  progress  on  a  smooth  surface,  where  there  is  noth- 
ing to  push  against.) 

Has  a  snake  bones  ?  Where  are  they  ?  ( ?7ri(ier  skin 
and  flesh.) 

17.  In  what  position  is  the  body  when  it  moves  ? 

18.  What  do  snakes  eat?  (Insects,  mice,  young  rats, 
gophers,  frogs,  etc.)  How  does  it  seize  the  prey  ?  (With 
its  mouth.) 

And  then  chews  it  ?    (No,  swallows  it  whole  !) 

Consider  the  food  and  tell  me,  are  these  snakes  use- 
ful to  man  or  not  ?  (Destroy  vermin  and  are  very  help- 
ful.) 

Should  they  be  killed  then  ?  {No  !  harmless,  useful, 
and  beautiful  creatures  should  not  be  killed  in  sport.) 

How  can  we  tell  the  poisonous  ones  ?  (Usually  have 
flat,  triangular  heads,  small  necks,  and  thick,  stumpy 
bodies.) 

19.  Do  snakes  drink?  (Yes,  they  need  plenty  of 
water.) 

What  do  they  breathe  f  (Air.)  Are  they  warm- 
blooded or  cold-blooded  ? 

20.  Do  snakes  make  a  home  ?  * 

*  Snake  "  holes  "  are  a  myth.  I  never  saw  a  snake  make  one, 
nor  even  enter  one  of  the  perpendicular  holes  in  our  prairies, 
nor  can  I  conceive  of  the  delicate  lips  and  jaws  being  used  for 
any  such  purpose  as  digging  a  hole  in  the  earth.  That  they  live 
in  logs,  clefts  in  the  rock,  etc.,  is  true. 
5 


50  SYSTEMATIC  SCIENCE  TEACHING. 

21.  Eggs. — Who  has  ever  seen  any  ?  Several  times  I 
have  turned  over  a  sod  in  the  garden  or  field  and  found 
twelve  to  twenty  longish,  soft-shelled,  white  eggs  stuck 
together  in  a  kind  of  string.  They  were  about  as  large 
and  long  as  the  first  joint  of  my  thumb.  No  snake  was 
about.  What  hatched  them  ?  (Sun.)  They  had  a  large 
yolk,  like  a  hen's  egg.  Judging  from  that,  would  you 
expect  the  young  to  be  able  to  run  and  feed  when 
hatched  ? 

Were  the  smallest  snakes  you  ever  saw  shaped  like 
their  mother  ?    (Yes.) 

22.  Can  a  snake  talk  f    (Hiss.) 

The  Frog. 

Choose  some  common  kind. 

Have  several  in  an  aquarium  for  the  school  to  watch 
for  some  days.  During  the  study  pass  these  around  the 
class. 

1.  Parts?— (Body,  head,  and  legs.) 
Shape  of  the  body  ?    (Pointed  behind.) 

2.  Has  the  frog  a  skin? 

Its  color  above  ?  Below  ?  What  use  is  this  coloring  ? 
(Protection.) 

How  does  it  fit  ?    (Loosely.) 

How  does  it  feel  ?    (Cold  and  smooth.) 

Is  it  dry  or  moist  ?  (A  frog  will  die  if  its  skin  is  kept 
dry  long.) 

3.  Is  there  anything  growing  from  the  skin  ?  {Noth- 
ing.) 

What  shall  we  call  such  a  skin  ?    (Naked.) 

4.  Head.— Shape  ?    Motion  ?    (Very  little.) 
Parts  ?    (Eyes,  ears,  nostrils,  and  mouth.) 

5.  Eyes.— Where  ?    (Almost  on  top  of  the  head.) 
Are  they  prominent  or  deeply  set  ? 

What  shape  ?    Color  ?    Large  or  small  ?    Use  ? 


ANIMALS.  51 

6.  Lids.— How  many  ?  Which  way  do  they  move  ? 
{Eye  seems  to  be  drawn  in.) 

Why  is  the  lower  one  transparent  ? 

7.  Eyeball. — Its  shape  ?  Can  the  frog  move  it  ?  Shape 
of  the  pupil  ? 

Does  the  size  of  the  pupil  vary  in  passing  from  strong 
light  to  shade  ? 

8.  Ears. — Where  ?    Any  external  opening  ? 

Does  your  own  experience  indicate  that  we  can  hear 
through  things  ? 

Have  you  any  reason  to  think  the  frog  can  hear  with 
closed  ears  ? 

Why  would  openings  or  projecting  ears  be  incon- 
venient ?    (So  much  in  the  water.) 

Who  has  been  in  swimming  ?  How  do  noises  sound 
when  the  head  is  under  water  ?    {Very  loud  and  distinct.) 

How  does  this  apply  to  a  frog  ? 

9.  Nostrils.— Where  located  ?  {High  up  on  end  of 
snout.) 

How  many  ?  Shape  of  openirig  ?  Can  the  opening 
be  closed  when  under  water  ?  Use  ?  What  does  it 
breathe  ?    (Air.) 

Is  a  frog  warm-  or  cold-blooded  ? 

10.  Mouth. — Where  placed  ?  A  cross  or  an  up  and 
down  opening  ? 

Motions  ?    Size  ?    Use  ? 

Parts  ?    (Lips,  tongue,  teeth,  and  saliva.) 

11.  Lips. — What  can  be  said  of  these  ?  (Thin  and 
delicate.) 

12.  Teeth. — Where  located  ?    (Upper  jaw  alone.) 
Size  ?    (Small.)    Use  ?    (Aid  in  holding  live  prey.) 

13.  Tongue.— Where  ?    How  fastened  ?    {In  front!) 
Shape?    Tip?     Surface?    (Sticky.) 

Motion  ?     (Thrown  forward  with  great  rapidity.) 

Use  ?    (Catch  insects,  etc.) 

How  is  the  food  swallowed  ?    (Whole.) 


52  SYSTEMATIC  SCIENCE  TEACHING. 

Of  what  use  is  the  saliva  ?    (Swallow  food  easily.) 

14.  What  do  you  notice  about  the  frog's  neck  f  (Al- 
most none.) 

15.  Legs.— How  many  ?    How  arranged  ?    (Pairs.) 
Are  they  alike  in  shape  ? 

Are  they  stiff  in  any  part  ?    What  makes  them  so  ? 
Where  are  the  bones  ?    ( Under  skin  and  flesh.) 
Have  the  legs  joints  ? 

16.  Forelegs.— How  many  joints  in  each  ?    (Two.) 
What  end  the  forelegs  ?    (Hands.) 

How  many  fingers  on  each  ?    (Four.) 
Which  is  the  longest  ?    (Third.)    The  shortest  ? 
Have  they  nails  on  the  end  ?    (None  !) 
Are  the  fingers  webbed  ?    What  are  they  (the  hands) 
used  for  ? 

17.  Hind  Legs.— How  many  joints  in  each  ?    (Three.) 
Which  is  the  knee  f    Which  the  heel  f 

How  do  the  hind  legs  compare  with  the  forelegs  ? 
(Longer  and  stronger.) 

How  many  toes  ?    (Five.)    The  shortest  ?    Longest  ? 

Are  they  webbed  ?    Have  the  toes  nails  ?    (None.) 

What  are  these  powerful  hind  legs  for  ?  (Leap  and 
swim.) 

What  is  remarkable  about  the  frog's  skin  ?  (Perfectly 
naked.) 

18.  Where  does  the  frog  live  ?  (Both  on  land  and  in 
the  water.) 

On  land  it  hops.    In  the  water  it  swims. 

Who  has  observed  the  habits  of  a  frog  when  it  is 
alarmed  and  jumps  into  the  water.  (Swims  off  a  little 
distance,  and  then  returns  to  some  bunch  of  weeds  or 
grass  and  rises  till  the  tip  of  the  nose  and  the  eyes  are 
just  out  of  the  water,  and  then  it  rests.  This  is  all  done 
so  quietly  that  it  is  rarely  observed.) 

Why  are  its  eyes  and  nostrils  set  so  high  on  the  head? 

19.  What  does  the  frog  eat  ?     (Insects  mainly.) 


ANIMALS.  63 

How  does  it  catch  its  prey  ?    (Sticky  tongue.) 
Are  frogs  useful  or  injurious  ?     (Useful.) 

20.  What  sounds  does  a  frog  make  ?    When  ? 

21.  Eggs. — Show  some  to  the  class. 

What  are  these  ?    Color  ?    Shape  ?    Number  ? 

Where  are  they  laid  ?    (On  weeds  in  the  water.) 

When  ?     (In  early  spring.) 

Are  they  cared  for  by  the  mother  frog  ? 

Is  the  yolk  large  or  small  ?     (Small.) 

Now  take  several  wide-mouthed  dishes  (milk  crocks 
are  good)  and  place  a  bunch  of  eggs  and  some  water 
plants  in  each.  Go  on  with  other  work  till  the  eggs 
have  hatched. 

Let  several  pupils  keep  a  "  diary  "  of  each  dish. 

22.  I  thought  these  were  frog's  eggs!  Do  these  little 
things  look  like  frogs  f 

What  can  you  tell  about  them  ?  (Tails,  bushy  gills 
at  sides  of  head,  big  heads,  two  eyes,  and  a  little  mouth. 
They  live  in  the  water  all  the  time  and  swim  with  their 
tails.    Certainly  this  is  not  froglike  !) 

We  will  wait  and  see  !  As  time  goes  on  record  the 
sprouting  of  the  hind  legs,  of  the  forelegs,  the  disappear- 
ance of  the  tail,  etc. 

Were  they  frog's  eggs  ?  Who  will  tell  me  the  life 
history  of  a  frog  ?     (Egg,  tadpole  with  gills,  etc.) 

What  about  the  egg  indicated  this  imperfect  condi- 
tion at  first  ?  (Small  yolk  could  not  feed  the  little  frog 
in  the  egg  long  enough.) 

The  Fish. 

Gold  fish  will  be  easy  to  keep  and  study,  but  any 
live  fish  that  can  be  kept  before  the  class  for  a  while 
will  do. 

Wide  dishes,  with  a  wire-netting  guard  to  prevent 
their  jumping  out,  and  from  four  to  six  inches  of  water 
have  proved  much  more  satisfactory  than  the  narrow- 


54  SYSTEMATIC  SCIENCE  TEACHING. 

mouthed  aquaria.    Feed  only  such  food  and  in  such 
quantity  as  the  fish  will  snap  up  entire. 

1.  Parts?— (Head,  body,  and  fins.) 

2.  Body. — Shape.  (Note  the  elegant  curves  of  least 
resistance  to  the  water.) 

What  is  the  body  covered  with  ? 

3.  Scales.— These  grow  from  ?    (Skin.) 

Colors  of  scales  ?  Can  you  imagine  any  use  for  these 
colors  ? 

Arrangement  of  scales  ?  (Regular  rows.)  Observe 
the  "  lateral  line  "  extending  from  head  along  the  side  to 
the  root  of  tail  fin. 

How  many  scales  are  there  in  this  lateral  line  ? 

If  you  were  making  an  artificial  fish,  would  you  begin 
at  the  head  or  tail  to  put  on  the  scales  ?    Why  ? 

What  shape  is  each  scale  ?  Is  the  edge  next  the  skin 
smooth  or  toothed  ?  What  kind  of  a  surface  has  each 
scale  ? 

Can  a  fish  move  its  scales  ? 

Can  you  find  parts  destitute  of  scales  ? 

4.  Head. — Deep  or  wide  ?  Gradual  or  abrupt  slant  on 
top? 

Has  it,  as  a  whole,  much  motion  ?     (No.) 
Parts  ?     (Eyes,  gill  covers,  nostrils,  mouth.) 

5.  Eyea — Where  placed  ?    Prominent  or  sunken  ? 
Shape?    Size?    Use?    Parts?     (Ball.) 

6.  Eyeballs.— Shape  ?  Motion  ?  Color  ?  Shape  of 
pupil  ] 

Any  lids?  (No.)  Tear?  (No.)  Why  are  none 
needed  ? 

7.  Gill  Covera- What  are  these  ?  (Several  horny 
flaps  covering  openings  in  the  sides  of  the  head.)  What 
motion  do  they  have  ? 

What  are  under  and  protected  by  them  ?  (Delicate, 
red  gills.) 

How  many  of  these  gills  under  each  ? 


ANIMALS.  55 

What  makes  them  so  red  ?    (Blood.) 

What  are  they  for  ?     (Instead  of  lungs.) 

But  how  does  the  fish  get  air  ?  Here  is  a  quart  jar 
entirely  full  of  pond  (or  spring)  water.  Can  you  see  any 
air  in  it  ?    (No.) 

Let  us  heat  it  over  this  register  (better,  plunge  into 
hot  water.) 

See  the  bubbles  of  air  rising  and  gathering  at  the  top ! 

Where  does  the  blood  in  the  gills  get  oxygen  ?  (From 
the  water.) 

Does  the  blood  give  out  COa  as  our  lungs  do  ?  (Test 
some  water  which  fish  have  been  in  with  lime-water,  and 
the  milky  coloration  will  show  COa.) 

How  does  the  fish  keep  the  water  flowing  over  the 
gills  ?  (Opening  and  closing  mouth,  forward  motion 
when  swimming,  and  by  flapping  side  fins  when  at  rest.) 

8.  Nostrils.— Where  ?  How  many?  Shape?  Use? 
(Smell.) 

9.  Mouth. — Where  ?    A  cross  or  up  and  down  slit  ? 
How  far  back  does  the  slit  extend  ? 

Large  opening  or  small  ?  Is  either  jaw  the  longer  ? 
Which  ? 

What  motion  to  jaws  ? 

Use  ?     (Take  in  water  to  gills  and  seize  prey.) 

Parts  ?    (Lips,  teeth,  tongue.) 

10.  Lips?— (Hard  and  firm.)  • 

11.  Teeth. — Where  ?  (Examine  by  feeling ;  they  may 
be  on  jaws,  tongue,  or  roof  of  mouth.)  What  kinds  ? 
Few  or  many  ? 

Which  way  do  they  point  ?  Use  ?  (Seize  and  hold 
live  prey.) 

12.  Tongue.— Where  ?  What  kind  of  a  substance  ? 
(Hard.) 

Where  fastened  ?    Shape  ?    Motion  ?     (Very  little.) 
Considering  the  way  fish  swallow  their  food  at  one 
gulp,  is  the  tongue  probably  of  much  use  for  taste  f 


56  SYSTEMATIC  SCIENCE  TEACHING. 

13.  Fins.— How  many  ?  Where  placed  ?  (This  is  very 
important.) 

Teacher  draw  the  fish  on  the  board  and  point  out 
the  dorsal  (back),  pectoral  (sides  of  head),  ventral  (on 
belly),  anal  (below,  in  front  of  tail),  and  caudal  (tail) 
fins. 

How  many  dorsal  fins  ?    If  one,  is  it  deeply  notched  ? 

Is  the  membrane  supported  by  spines  or  "  soft  rays  "  ? 

How  many  spines  ?    How  many  soft  rays  ? 

Is  there  a  skinny  (adipose)  fin  near  the  tail  ? 

How  many  spines  and  soft  rays  in  the  pectoral  fins  ? 

Where  are  the  ventrals  placed  ? 

How  many  spines  and  soft  rays  in  each  ? 

How  many  in  the  anal  fin  ?  Does  it  extend  to  the 
caudal  ? 

Is  the  caudal  forked  or  rounded  ?  Does  the  backbone 
seem  to  end  at  the  center  or  run  into  the  upper  lobe  of 
the  caudal  ? 

What  are  the  different  fins  for  ? 

14.  Where  do  these  fish  live  ? 

15.  Do  they  make  a  home  of  any  kind  ?    (No.) 

16.  How  does  a  fish  move?     (Swim,  jump,  dart,  etc.) 
What  position  is  the  body  in  when  moving  ?     (Hori- 
zontal.) 

Has  it  a  backbone  ?  With  joints  ?  (Remember  fish 
at  the  table.) 

What  kind  of  a  skeleton  has  it  ?  (Internal,  bony,  and 
jointed.) 

17.  What  does  it  eat? 
How  does  it  take  the  food  ? 
Does  it  chew  its  food  ? 

18.  Does  a  fish  make  any  sounds  ?    Can  it  hear  ? 

19.  Who  has  seen  young  fish  ?  Do  they  resemble  the 
mother  ? 

The  eggs  are  laid  in  the  water  and  neglected  by  the 
mother. 


,  ANIMALS.  57 

What  do  you  think  happens  to  many  of  them  ? 
(Eaten.) 

Yes,  many  water  animals  are  fond  of  eggs  and  eat 
all  they  can  find.  How  do  fish  manage  to  avoid  destruc- 
tion. (They  lay  a  great  many  eggs,  millions  in  some 
cases,  and  so  enough  escape  and  hatch  to  keep  the  waters 
supplied  with  fish.) 

20.  Who  can  think  of  any  resemblance  between  the 
six  animals  we  have  studied  ?  (Boy,  cow,  hen,  snake, 
frog,  and  fish.) 

1.  All  have  an  inside,  bony,  jointed  skeleton. 

2.  All  have  a  backbone. 

3.  The  organs,  eyes,  ears,  limbs,  etc.,  are  paired,  and 
the  two  sides  of  the  body  alike. 

The  Moth* 
Should  it  be  impossible  to  get  caterpillars  and  cocoons, 
postpone  this  lesson  till  such  time  as  they  can  be  had. 
Some  butterfly  will  do  just  as  well,  except  that  its  cater- 
pillar spins  no  cocoon. 

1.  Parts?— (Head,  thorax,  abdomen,  wings,  and  legs.) 
Into  how  many  parts  does  the  body  of  the  moth  seem 

divided  ?     (Three.) 

2.  Head.— Shape  ?  Motions  ?  Covering  ?  Parts  ? 
(Eyes,  antennae,  tongue.) 

3.  Eyes.— Where  ?  Size  ?  Color  ?  Surface  ?  Are 
they  simple  or  compound  ?  (Compound.  The  simple 
eyes  on  the  top  of  the  head  will  probably  not  be  seen.) 

What  is  a  "  compound  "  eye  ?  t 

Can  the  eyes  be  moved  ?    Their  use  ? 

4.  Antennae.- Where  are  they  fixed  ?  Shape  ?  Mo- 
tion ?  Number  ?  Use  ?  (For  feeling  and  smell.)  Are 
they  clubbed  f    (Not  in  moths.) 

*  Cecropia  or  other  large,  common  sort, 
f  Show  drawings  and  explain.    See  Orton,  p.  182,  or  other 
zoology. 


58  SYSTEMATIC  SCIENCE  TEACHING.  , 

5.  Tongue. — Where  fastened  ?  How  held  when  not 
in  use  ?    (Coiled.) 

Length  ?  Motion  ?  Use  ?  (To  draw  up  the  nectar  of 
flowers.) 

6.  Thorax — Where  is  this  ?  (Between  head  and  ab- 
domen.) 

What  shape  is  it  ?    Covered  with  ?    StiflP  or  not  ? 
What  grow  from  it  ?     (Two  pairs  of  wings  and  three 
pairs  of  legs.) 

7.  Wings.— How  many  ?  Where  placed  ?  How  held 
when  the  moth  is  at  rest  ?    Which  overlap  the  others  ? 

What  use  ?    Are  they  equal  in  size  ?    Which  largest  ? 
What  are  they   covered  with  ?    (Loose  scales.)    Is 
there  any  order  in  their  arrangement  ? 

How  stiffened  ?     ("  Veins,"  really  air  tubes.*) 

8.  Fore  Wings.— Shape  ?  Front  margin  ?  Hind  mar- 
gin ? 

How  are  the  principal  veins  arranged  ? 
Describe  the  colors  above  ?    Below  ? 
Are  there  joints  in  them  ?     (No.) 

9.  Hind  Wings.— Shape  ?  Front  margin  ?  Hind  mar- 
gin ?    Why  is  the  hind  margin  flexible  ? 

How  are  the  principal  veins  arranged  ? 
Describe  the  colors  of  upper  side  ?    Of  lower  ? 
Any  joints  in  them  ? 

10.  Remembering  that  this  moth  lives  on  trees  and 
hides  among  the  crevices  of  bark  and  small  limbs,  can 
you  see  any  use  in  the  position  of  its  wings  when  at  rest? 

In  the  colors  of  the  upper  or  lower  surfaces  of  the 
wings  ? 

11.  Legs.— How  many?  (Six.)  Growing  from?  (The 
thorax.) 

How  arranged?    (In  pairs.)    Use?    (Walk  and  climb.) 

12.  Front  Legs.— Which  way  directed  ?  How  many 
joints  ? 

*  See  Orton,  pp.  114,  115. 


ANIMALS.  59 

What  end  them  ?  (Feet.)  Can  you  count  the  joints 
in  each  foot  ? 

What  is  the  last  one  ?     (Pair  of  hooks.) 

13.  Middle  Legs. — Which  way  directed  ?  How  many 
joints. 

How  many  joints  to  the  feet  ?    The  last  one  is ? 

14.  Hind  Legs.— Which  way  directed  ?    Joints  ? 
Joints  in  feet  ?    Last  joint  is  ? 

15.  Abdomen.— Shape  ?    Covered  with  ?    Colors  ? 
Motion  ?    Any  parts  ?     {Joints^  but  they  can  hardly 

be  counted.) 

16.  Where  does  this  moth  live?  (On  trees  and  in 
the  air.) 

How  does  it  move  f  (Mostly  flies.)  When  ?  (At 
night.) 

What  does  it  eat  ?     (Nectar  of  flowers.) 

It  seems  fond  of  that  from  deep,  tubular  flowers. 
How  does  it  get  it  ?  (With  long  tongue.)  Does  it  get  a 
meal  in  one  flower  ? 

Of  what  use  are  these  visits  from  one  flower  to  an- 
other to  the  flowers  themselves  ?  (Carry  pollen.  See 
Morning  Glory,  Step  XXIII.) 

17.  What  part  have  we  not  yet  considered  ?    (Nose.) 
Have  you  seen  anything  like  a  nose  ?     (No.) 

How  do  moths  breathe  air  ? 

They  do  this  by  openings  along  the  sides  and  not 
through  the  mouth. 

These  we  shall  see  better  in  the  caterpillar. 

18.  What  did  these  moths  come  from  ?  (Long,  brown, 
silken  cocoons.) 

What  made  the  cocoon  ?  (Caterpillar.)  Let  us  study 
one  of  these. 

The  moth  lays  eggs.    Where  ?     (On  food-plant.) 

How  does  she  know  what  the  young  eat  ? 

These  eggs  hatch  by  what  heat  ?  (Sun.)  Into  ?  (Cat- 
erpillars.) 


60  SYSTEMATIC  SCIENCE  TEACHING. 

19.  Caterpillar.— Colors  ?    Why  these  colors  ? 
Parts  ?     (Body,  head,  and  feet.) 

How  many  parts  (or  rings)  to  the  whole  body  ?    (Thir- 
teen.)    What  covering  ? 

20.  Head.— Color  ?    Parts  ?    (Simple  eyes  and  jaws.) 
How  many  eyes  ?    Where  placed  ?    What  for  ? 
Which  way  do  the  jaws  open  ?    (Side  to  side.)    Use  ? 

(Gnaw  leaves,  etc.) 

Is  the  head  movable  ? 

21.  Body.  —  Composed     of    how     many     segments  ? 
(Twelve.) 

What  is  the  first  segment  called  ?    (Head.) 

Second  segment.    Size  ?    Color  ?    What  appendages  ?  * 

(Pair  of  legs  and  breathing-hole.) 

Third  segment.     Size  ?    Color  ?    Appendages  ?    (Pair 

of  legs.) 

Fourth  segment.    Size  ?    Color  ?    Appendages  ?    (Pair 

of  legs.) 

Fifth  segment.    Size  ?    Color  ?    Appendages  ?    (Only 

a  breathing-hole.) 

Sixth  segment.     (Same.) 

Seventh  segment.    Size?   Color?  Appendages?    (Pair 

fleshy,  hooked  legs  and  breathing-hole.) 

Eighth  segment.  Size?  Color?  Appendages?  (Same.) 
Ninth  segment.  Size?  Color?  Appendages?  (Same.) 
Tenth  segment.  Size?  Color?  Appendages?  (Same.) 
Eleventh  and  twelfth  segments.  Size  ?  Color  ?  Ap- 
pendages ?     (Only  breathing-holes.) 

Thirteenth  segment  ?     Size  ?     Color  ?     Appendages  ? 

(Pair  of  fleshy  legs.) 

How  many  jointed  legs  ?    (Six.)    How  many  fleshy 

legs  ?  (Ten.)  How  many  together  ?  (Sixteen.) 
How  many  breathing-holes  ?  (Twenty-two.) 
Is  a  caterpillar  warm  or  cold  blooded  ?    (Cold.) 

*  These  are  not  the  same  in  all  caterpillars. 


ANIMALS.  61 

How  does  it  move  ?    (Crawls.) 

Has  it  any  hones  f  (No.)  Joints  ?  (Between  each 
ring  and  on  fore  leg's.) 

Where  does  the  skeleton  of  moth  and  caterpillar  seem 
to  be  ?    (Outside !) 

22.  Food  ? — What  does  it  eat  ?    (Leaves.) 

As  it  grows,  how  does  it  manage  with  its  skeleton  out- 
side f  (Sheds  its  skin  or  molts  frequently,  four  or  five 
times,  and  after  each  molt  swells  out  and  grows  rapidly 
for  a  time,  and  then  waits  till  the  next  molt  before 
growing  again.) 

23.  When  fully  grown  a  caterpillar  stops  eating  and 
hunts  for  a  place  to  spin  its  cocoon.  What  place  does  it 
usually  select  ? 

What  is  a  cocoon  made  of  ?     (Silk.) 

Where  does  the  silk  come  from  ?  (An  opening  be- 
low the  jaws,  out  of  which  flows  a  fluid  that  almost 
instantly  hardens  into  a  thread  of  silk.) 

Now  have  such  of  the  pupils  as  have  seen  it  done, 
describe  the  process  of  spinning  a  cocoon. 

24.  Inside  this  silken  nest,  what  happens  to  the  cater- 
pillar after  the  cocoon  is  made  ?  (Turns  to  a  brown, 
mummy-like  pupa !) 

Does  this  show  life  ?    (A  little.) 

Does  it  look  like  a  moth  ?    (No.) 

Those  who  have  examined  pupa?  tell  us  that  nearly  all 
traces  of  the  caterpillar  seem  to  dissolve  away,  and  from 
the  liquid  contents  grows — what  ?     (The  moth  !  *) 

Who  taught  the  moth  to  lay  her  eggs  on  some  par- 
ticular plant  ? 

What  prompted  the  untaught  and  inexperienced  cater- 
pillar to  select  a  suitable  spot  and  there  spin  a  cocoon  ? 

*  Orton,  note  118,  p.  390. 


02  SYSTEMATIC  SCIENCE  TEACHING. 


Crayfish^  or  Crab. 

This  study  should  come  in  early  spring,  when  cray- 
fish with  young  can  be  found. 

I  should  advise  taking  the  study  of  mother  and  young, 
and  then  placing  one  family  in  each  of  two  or  three  wide 
dishes  and  letting  the  pupils  feed  and  rear  the  young, 
which  will  be  very  useful  to  distribute  to  the  class  when, 
at  this  later  date,  the  study  is  completed. 

If  fresh  specimens  can  not  be  had,  use  those  prepared 
as  suggested  in  Step  IX  with  the  preserving  fluid. 

(Huxley's  Crayfish  should  be  read — at  least  the  first 
one  hundred  and  seventy-three  pages — and  should  be 
used  by  each  teacher,  specimens  in  hand.) 

1.  Parts?— (Body,  legs,  and  abdomen.) 

2.  Body. — How  does  it  feel  ?    (Hard,  smooth,  and  cold.) 
What  shall  we  call  the  covering  ?    (Shell.) 

Its  color  ?  Drop  a  bit  of  dry  shell  in  hydrochloric 
acid  ?    (Effervesces.) 

What  is  left  ?    (A  bit  of  tough  skin.) 

What  is  the  covering  then  ?  (A  tough  skin  hardened 
with  lime.) 

Where  does  the  skeleton  seem  to  be  ?    (Outside.) 

Has  the  crayfish  a  head  f 

What  seems  to  have  happened  to  it  ?  (United  with 
the  body.) 

What  did  we  call  the  second  part  of  the  moth  ? 
(Thorax.) 

When  we  find  the  head  and  body  united  we  call  it  a 
head  thorax. 

3.  Head  Organs  ?— (Eyes  and  antennae,  as  seen  from 
above.) 

What  is  peculiar  about  the  eyes  ?     (On  movable  stalks.) 
Are  they  simple  or  compound  eyes  ?    (Compound.) 
Have  they  eyelids  ?    (No.) 


ANIMALS.  63 

4.  Antennae. — How  many?    (Two  long  and  four  short.) 
What  shape  ?     How  constructed  ?     (Many  joints.) 
Which  way  can  they  be  directed  ?     (All  ways.) 

As  you  observe  the  crayfish  employ  them,  what  use 
do  they  seem  to  be  ?    (Feel.) 

Scientific  men  have  discovered  that  the  short  antennae 
are  also  organs  of  smell  and  hearing* 

5.  Mouth.— Has  the  crayfish  any  mouth  ?  Where  is 
it  ?    (Under  side.) 

Turn  the  animal  on  its  back  and  see  the  mouth. 

Which  way  do  the  jaws  and  parts  about  it  move? 
(Side  to  side.) 

How  many  parts  are  there  around  the  mouth  ?  (Ten 
in  five  pairs.) 

Can  you  make  out  the  use  of  any  of  them  ? 

Yes,  they  aid  in  holding  and  tearing  up  the  food  ready 
to  be  swallowed. 

6.  Food. — Do  any  of  you  know  what  this  is  ?  t 

How  is  live  food  caught  ?     (By  big  pinchers  or  claws.) 
How  chewed  up  ?    (By  foot  jaws  and  hard  mandi- 
bles.)    Could  we  examine  the  stomach  we  should  find 
some  hard,  grinding  teeth  there  ! 

7.  Legs. — What  else  do  you  notice  on  the  underside? 
(Legs.) 

How  many?    (Ten.)     How  arranged?     (In  five  pairs.) 
Let  us  study  these  one  by  one,  beginning  with  the  big 
front  ones. 

8.  First  Pair  of  Legs.— What  are  these  usually  called  ? 
(Big  claws.) 

*  Huxley,  pp.  114-117. 

f  Huxley,  p.  9,  gives  an  extended  bill  of  fare  for  the  English 
crayfish.  Our  American  ones,  as  far  as  I  have  observed,  eat 
small  fish,  pollywogs,  earthworms,  and  decaying  flesh,  especially 
of  fish.  They  seem  to  play  an  important  part  as  scavengers  in 
our  ponds  and  rivers. 


64:  SYSTEMATIC  SCIENCE   TEACHING. 

Which  way  are  they  dir-ected  ? 

Where  attached  ?    How  many  joints  in  each  ?     (Six.) 

Gently  move  the  leg,  and  observe  the  varied  motion 
of  these  joints. 

What  peculiar  motion  has  the  sixth  joint  ?  (Like  a 
thumb.) 

What  is  peculiar  about  the  fifth  ?  (Prolonged  into  a 
*'  finger  "  to  meet  the  sixth.) 

What  do  you  notice  about  the  inner  edges  of  the  fifth 
and  sixth  ?     (Rough.)     About  the  tips  ?    (Hooked.) 

What  is  the  use  of  these  roughnesses  ?  (Hold  things 
better.) 

9.  Second  Pair  of  Legs.— Where  are  these?  (Close 
behind  the  first.)     Which  way  directed  ? 

How  many  joints  ?  (Seven.)  What  is  noticeable 
about  the  sixth  and  seventh  ? 

10.  Third  Pair  of  Legs.— Where  ?  Directed  which 
way  ?     Number  of  joints  ? 

How  about  the  sixth  and  seventh  ?  (Like  a  thumb 
and  finger.) 

11.  Fourth  Pair  of  Legs.— Where?  Directed  which 
way  ?    Number  of  joints  ?    The  seventh  ? 

12.  Fifth  Pair  of  Legs.— Where  ?  Directed  which 
way  ?    Number  of  joints  ?    The  seventh  ? 

What  use  for  these  five  pairs  of  legs  ?  (Walk,  fight, 
catch  food,  etc.) 

Which  can  best  be  used  to  take  food  ?  (First  three 
pairs.) 

13.  Abdomen.— Where  ?  (Attached  to  hinder  end  of 
head  thorax.) 

Shape  ?  (Convex  above  and  flattened  below.)  Its 
motion  ?     (Up  and  down.) 

How  many  segments  in  it  ?  (Seven.)  How  arranged  ? 
(The  hind  edge  of  each  overlapping  the  front  edge  of  the 
next.) 

How  connected  ?     (By  tough,  flexible  skin.) 


ANIMALS.  65 

14.  First  Segment. — Note  its  shape,  comparative  size, 
edges,  etc. 

Has  it  any  appendages  ?     (A  pair.)  * 

15.  Second  Segment. — Note  as  above.  Appendages  ? 
(A  pair.) 

16.  Third  Segment— Note  as  above.  Appendages? 
(Pair  of  swimmerets.) 

How  are  these  swimmerets  constructed  ?  What  mo- 
tion have  they  ? 

17.  Fourth  and  Fifth  Segments.— About  the  same. 

18.  Sixth  Segment.— What  grow  from  it  ?  (Two  hroad 
swimmerets.) 

Turned  which  way  ?    How  many  pieces  in  each  ? 
What  motion  ?     (Downward,  like  the  last  segment.) 

19.  Seventh  Segment— Shape  ?  Size  ?  Any  append- 
ages?   (No.) 

Joints  ?  (One.)  Motion  ?  (Down.)  Tliis  and  the 
four  flaps  of  the  sixth  segment's  swimmerets  together 
form  the  "  telson." 

What  is  the  use  of  the  telson  ?  (To  swim  backward 
with.) 

Of  what  use  are  the  other  swimmerets  ?  (Gently  to 
paddle  ahead,  and  in  the  mother  crayfish  to  carry  the 
eggs  and  young.) 

20.  Breathing. — When  a  live  specimen  is  still,  watch 
closely  and  see  if  there  is  any  motion  to  the  overhang- 
ing edges  of  the  back.  With  a  glass  tube  or  dropper 
drop  a  little  colored  fluid  into  the  water  just  by  the  side 
of  the  first  segment  of  the  abdomen.  Does  it  show  a  cur- 
rent in  the  water  ? 

Which  way  ?  {Forward,  under  the  sides  of  the 
thorax.) 

Watch  in  front  by  the  sides  of  the  head  and  see  a 

*  What  these  are  depends  on  sex,  and  will  be  "  hooks  "  in  the 
male  and  "  swimmerets  "  in  the  female. 
6 


ee  SYSTEMATIC  SCIENCE  TEACHING. 

fluttering  organ.  Under  the  broad,  overhanging  mar- 
gins of  the  thorax  are  many  pairs  of  delicate  gills,  in 
which  the  blood  is  purified. 

What  does  the  crayfish  breathe  ?     (Air  in  water.)  * 

Where  is  it  taken  in  ?  (Behind.)  And  is  let  out  ? 
(In  front.) 

How  is  the  water  changed  when  the  crayfish  swims 
backward  ? 

When  lying  still  ?  (The  little  fluttering  paddles  keep 
drawing  it  out  in  front,  and  of  course  more  has  to  come 
in  behind.) 

What  similar  device  in  another  water-breathing  ani- 
mal ?    (Pectoral  fins  of  the  fish.) 

21.  Where  does  the  crayfish  live  ?  (In  water  of 
streams  and  ponds.) 

When  a  pond  dries  up,  as  the  sloughs  of  the  wide 
prairies  do  almost  every  year,  how  does  it  manage  ?  (Digs 
a  well.) 

As  the  water  keeps  sinking  in  the  soil  ?  (Digs  deeper 
and  deeper.) 

What  does  it  dig  with  ?    (Big  claws.) 

When  ?     (At  night.) 

How  does  he  carry  the  clay  and  gravel  to  the  top  ^ 
(Under  its  curved  abdomen.) 

What  use  to  plants  is  there  in  bringing  up  so  much 
of  the  deeper  layers  of  earth  as  the  hundreds  of  crayfish 
on  each  acre  do  ?  (Brings  up  new  soil  and  makes  it  easy 
for  roots  to  grow  down.) 

What  damage  to  man,  when  crayfish  honeycomb 
the  banks  of  streams,  levees  along  large  rivers,  etc.,  with 
their  holes  ?  (Makes  them  weak,  till  at  last  they  may 
break  or  cave  in.) 

22.  Do  crayfish  make  a  home  f  (Not  for  a  family  to 
live  in.) 

*  Huxley,  pp.  79-81. 


ANIMALS.  67 

When  are  the  eggs  laid  ?    (In  early  winter.) 

How  many  ? 

What  queer  way  of  caring  for  them  ?  (They  stick 
to  the  swimmerets  of  the  mother's  abdomen.)  * 

Look  at  the  picture  in  Huxley  and  see  the  queer  claws 
with  which  the  young  hang  on  to  the  old  egg  cases  till 
they  are  old  enough  to  leave  the  mother. 

Do  the  young  resemble  the  mother  ?     (Yes.) 

23.  How  can  the  young  gi^ow  when  incased  in  a  stiff 
outside  skeleton  ?     (Shed  shells.) 

Yes,  this  is  done  several  times  the  first  year,  and  after 
each  molt  the  crayfish  rapidly  expands  while  the  skin  is 
soft,  and  then  a  new  shell  forms.  Frequently  crayfish 
are  found  with  one  big  and  one  little  front  claw. 

How  did  it  happen  ?  (Sometimes  a  claw  is  lost  in 
molting  or  by  accident,  and  then,  wonderful  to  tell,  an- 
other sprouts  and  grows.) 

24.  Are  the  two  sides  of  the  body  alike  ?  Name  the 
organs  on  one  side  in  order  from  front  to  back. 

Are  they  warm  or  cold  blooded  ? 

What  is  the  color  of  the  blood  ?    (Watery.) 

SNAIL  {Limncea). 

Search  ponds  and  ditches  for  some  of  the  air-breath- 
ing pond  snails,  and  ^gather  enough  so  that  each  member 
of  the  class  can  have  a  couple  to  study.  Also  gather 
plenty  of  the  dead  shells,  and  it  will  be  well  to  add  dead 
shells  of  Planorbis  or  other  /e/f-handed  shell. 

Place  the  live  ones  in  shallow  dishes  or  glass  jars, 
with  some  pond  weeds,  several  weeks  before  the  study, 
that  the  pupils  may  observe  their  habits. 

Morse's  First  Book  in  Zoology  will  be  very  helpful  in 
this  study. 

1.  Give  shells  to  the  class. 

*  Huxley,  pp.  40,  41. 


68  SYSTEMATIC  SCIENCE  TEACHING. 

How  many  parts  to  this  snail  shell  ?    (One.) 

Its  color  ? 

General  shape  ? 

What  is  at  the  large  end  ?    (Opening.) 

We  call  this  the  aperture. 

What  do  you  notice  about  the  other  end  ?    (Pointed.) 

Hold  the  pointed  end  (apex)  up  and  the  aperture  to- 
ward you. 

On  which  side  is  the  opening  ?    (Right  or  left.) 

Begin  at  the  apex  and  follow  the  spiral  crease  to  the 
bottom. 

Where  does  it  end  ? 

These  are  called  the  sutures,  and  the  bulges  between 
them  are  the  whorls. 

Do  you  notice  any  other  lines  ?  (Across  from  one 
suture  to  another.) 

The  thin  edge  of  the  aperture  is  called  the  lip. 

How  do  these  cross  lines  run  witii  regard  to  the  lip  ? 
(Parallel.) 

They  are  called  lines  of  growth. 

How  does  the  shell  feel  ?    (Hard.) 

Drop  a  poor  one  in  acid.     (Effervesces  and  dissolves.) 

What  are  they  made  of  ?    (Carbonate  of  lime.) 

2.  Aperture. — Shape  of  opening  ?  Is  the  lip  thick,  or 
thin  ? 

A  regular  or  a  broken  curve  ?  All  try  and  find  as 
many  kinds  of  snail  shells  as  you  can,  and  let  me  see 
them. 

3.  Now  give  live  snails  in  sauce  dishes  of  water. 
What  is  inside  these  live  shells  ?    (Animals.) 
What  do  we  call  its  skeleton  ?     (Shell.) 
Where  is  this  skeleton  ?     (Outside.) 

How  does  the  animal  feel  f    (Soft  and  cold.) 
Its  color  ? 

Parts  ?  (Head,  foot,  breathing  tube.)  See  Morse, 
p.  11. 


ANIMALS.  69 

4.  Foot.— Where  is  the  foot  ?  (On  the  stomach.)  Its 
shape  ?  Motion  ?  (Watch  a  snail  crawl  up  the  side  of  a 
glass  jar).  Use  ?  Does  it  carry  a  little  plate  of  shell  on 
the  back  of  the  foot  to  close  the  aperture  when  in  ? 
If  not,  can  you  find  such  a  snail  ?     (Morse,  p.  12.) 

5.  Head.— Where  ?    (Front  of  foot.) 
Parts  ?    (Mouth,  feelers,  eyes.) 

Where  is  the  mouth  ?  (On  the  underside,  near  the 
front.)  Shape  ?  Motion  ?  (This  can  be  seen  as  the  snails 
crawl  on  the  glass  or  float,  foot  up,  on  the  surface  of  the 
water.) 

Watch  for  a  little  white  speck  going  in  and  out  of 
the  mouth.    This  is  the  tongue,  a  most  wonderful  thing.* 

Small  as  it  is,  it  has  hundreds  of  beautifully  formed 
and  very  hard,  platelike  teeth,  arranged  in  regular  order 
on  its  surface,  making  it  a  very  efiicient  organ  to  file  off 
bits  of  the  food.  As  it  wears  out  at  the  tip,  it  grows  be- 
hind. Can  you  find  snails  having  the  mouth  differently 
situated  ?  t 

6.  Tentacles,  or  feelers.    Where  are  they  placed  ? 
How  many  ?    Shape  ?    Motion  ?    Use  ?     (To  feel  with, 

and  perhaps  hear.) 

Can  you  find  snails  with  a  different  number  or  form 
of  tentacles  ? 

7.  Eyes.— Where  placed  ?    How  many  ? 
Are  they  simple,  or  compound  ?     (Simple.) 

Can  you  find  snails  with  the  eyes  differently  placed  ?  | 

8.  "Where  do  these  snails  live?  (In  ponds  and  still 
water.) 

How  do  they  move  ?     (Glide  along  on  the  single  foot.) 
What  do  they  eat  ?    (Minute  plants  usually,  but  do 
not  refuse  animal  food  if  found.)  * 

*  See  cuts  of  the  lingual  ribbon  in  Tenny,  402 ;  Orton,  65 ;  or 
other  Zoology. 

t  Morse,  p.  12.  J  Morse,  p.  16. 

**  I  have  seen  a  dead  hog  floating  in  a  pond  literally  black 


70  SYSTEMATIC  SCIENCE  TEACHING. 

9.  How  do  they  breathe  ?  If  the  pupils  have  been 
watching"  the  snails  they  can  hardly  have  failed  to  see 
them  rise  to  the  surface,  turn  over,  foot  up,  and  with  a 
tiny  pop !  open  their  breathing  tube  at  the  surface. 
After  a  moment  this  is  closed  and  withdrawn  into  the 
shell,  the  snail  turns  over,  and  descends  again  to  feed. 

Try  and  find  snails  which  never  come  up  to  breathe. 
These  have  gills. 

10.  Egg&— Where  laid  ?  How  many  ?  How  laid  ? 
(In  jellylike  cluster.) 

Find  how  long  it  takes  them  to  hatch. 

Can  the  little  snails  move  and  feed  when  hatched  ? 

Do  they  resemble  the  mother  ?     (Yes.) 

Can  you  find  snails  which  lay  their  eggs  singly  ?  * 

Which  lay  little  live  snails  ?  t 

11.  How  can  the  little  snails  grow,  living  in  a  hard 
shell  ?  (Covering  the  body  is  a  skin  called  the  mantle, 
which  is  able  to  form  shell,  and  as  the  snail  grows  it  con- 
tinually adds  on  to  its  shell.)  Where  ?  (At  the  lip.) 
Why  are  the  lines  parallel  with  the  lip  called  lines  of 
growth  ?  (Because  they  show  the  successive  additions 
made  to  the  shell.) 

Where  does  the  lime  for  the  shell  come  from  ?  (Snail's 
food.) 

Why  are  snails  especially  abundant  in  districts  where 
there  is  much  lime  in  the  soil  and  water  ? 

The  Clam  {Fresh-water). 

Having  studied  the  hard-shelled  Venus  in  a  previous 
step,  I  would  here  choose  the  fresh-water  clam  (although 
any  bivalve  will  do  by  making  the  necessary  changes  in 

with  snails,  and  frequently  seen  them  clustered  on  smaller  de- 
caying animals  in  the  water. 

*  Morse,  p.  20. 

f  Morse,  Figs.  15  and  16,  Paludina. 


ANIMALS.  Yl 

what  follows).  Have  the  boys  aid  in  collecting  enough 
pairs  of  shells  so  that  each  pupil  may  have  one.  Wash 
clean  and  tie  mates  together.  Have  a  few  live  ones  of  the 
same  species  in  dishes  of  water,  with  a  sand  or  mud  bot- 
tom for  them  to  move  about  in.  After  these  have  been 
under  observation  for  some  days,  begin  the  study. 

1.  Shell  outside.— Shape  as  a  whole  ?  Surface  ?  (Usu- 
ally with  a  kind  of  skin  or  "  epidermis.")     Colors  ? 

Is  the  epidermis  worn  off  at  any  place  ?  (That  knob 
is  the  "beak.") 

What  else  about  the  outside  of  the  shell  ?    (Lines.) 

Where  do  these  begin  and  end  ?  Where  smallest  ? 
(Around  beak.) 

How  is  their  direction  related  to  the  edge  of  the  shell  ? 
(Concentric.) 

What  did  we  see  like  them  in  the  snail  ?  (Lines  of 
growth.) 

Do  the  edges  of  the  shell  fit  tightly  all  around  ?  (Open 
cracks,  high  up  behind  and  low  down  in  front.) 

Hold  the  shell  with  the  beak  to  the  left  and  edges 
down.  What  do  you  notice  on  the  upper  side  ?  (Brown- 
ish substance.) 

This  is  the  ligament.  Now  untie  your  shells.  (They 
open  a  little.)  * 

When  the  clam  is  alive  the  ligament  is  like  India 
rubber. 

When  the  shell  is  closed,  what  happens  to  the  liga- 
ment ?     (Stretched.) 

What  is  it  that  causes  motion  in  our  bodies  ?    (Muscles.) 

Clams  have  muscles  also.  To  do  which,  open  or  close 
the  shell  ?    (Close.) 

What  opens  it  again  ?     (The  ligament  contracts.) 

How  many  parts  to  a  clam  shell  ?  (Two.)  Are  they 
alike  in  size  and  shape  ? 

*  Show  this  with  a  fresh  dead  shell  if  the  others  are  too  old. 


72  SYSTEMATIC  SCIENCE  TEACHING. 

2.  Shell  inside?    Surface?    (Smooth  and  concave.) 
Colors  ?      What    running    around    near  the  edge  ? 

(Line.) 

This  is  called  the  pallial  (mantle)  line. 

What  do  you  find  at  either  end  of  this  line  ?  (Oval 
spots.) 

Those  are  called  muscle  impressions,  as  they  are  where 
the  muscles  closing  the  shell  are  fastened. 

Are  the  two  halves  of  the  shell  exactly  alike  ?  (Note 
differences  in  the  teeth  of  the  hinge,  just  below  the  liga- 
ment.) 

What  substance  are  clam  shells  made  of  ?  (Car- 
bonate of  lime.)     Put  a  piece  in  acid. 

(It  is  a  great  temptation  here  to  dissect,  but  I  think, 
on  the  whole,  the  temptation  is  to  be  resisted.  Nine  to 
ten  year  children  are  not  old  enough  to  do  it,  and  I 
should  adhere  to  what  can  be  seen  and  learned  with- 
out it.) 

3.  The  Clam  itself.— Where  is  it  ?    (Inside  the  shell.) 
What  parts  can  you  ever  see  ?     (White  foot  and  deli- 
cate fringe.) 

Where  is  the  foot  put  out  ?  (Through  the  crack  be- 
low the  beak.) 

What  color  is  it  ?  Hard  or  soft  ?  Motion  ?  (Out 
and  in.) 

Use  ?    (Clam  pulls  itself  through  the  mud  with  it.) 

4.  Siphons.— Where  is  the  "  fringe  "  put  out  ?  (Through 
the  crack  back  of  the  ligament.) 

When  out,  very  gently  drop  some  colored  liquid  (in- 
digo or  red  ink)  in  the  water  near  them.  Can  you  see 
any  movement  in  the  water  ? 

Which  way  ?     {In  at  lower  side  and  out  at  upper.) 

The  "  fringe  "  is  the  ends  of  the  two  siphons  through 
which  water  is  passed  in  and  out  of  the  clam. 

Can  you  think  what  it  breathes  ?  (Air  in  water.) 
What  with  ?    (Gills.) 


ANIMALS.  ^3 

Yes,  you  are  right,  and  some  day  I  hope  you  can  see 
these  curious  gills. 

5.  The  Young. — Were  the  smallest  clams  you  ever 
saw  clam-shaped  ? 

The  mother  clam  has  a  curious  way  of  carrying  her 
eggs  in  her  gills  till  they  hatch.  Then  the  little  ones, 
much  unlike  their  mother,  pass  out  with  the  current  of 
water  through  the  upper  siphon  and,  if  they  can,  fasten 
on  to  a  fish  till  they  have  grown  somewhat  larger  and 
become  really  like  clams.* 

In  what  ways  are  snails  and  clams  alike  f  {Limy 
shells  covering  soft  bodies.) 

Earthworm. 

Place  a  number  of  worms  on  some  loose,  moist  soil 
in  a  box,  and  observe  their  way  of  penetrating  the 
ground.  On  the  surface  scatter  a  few  leaves,  some  blunt 
and  some  pointed,  and  test  some  of  the  conclusions  re- 
garding the  intelligence  of  worms  Darwin  speaks  of  in 
his  Vegetable  Mold  (pp.  32  and  33,  and  65-91).  Any 
one  will  be  greatly  interested  in  at  least  the  first  two 
chapters  of  this  classic  study  of  a  remarkable  animal, 
and  in  what  follows  my  own  observations  have  been 
greatly  aided  by  his  wise  guidance.  At  least  once  dur- 
ing the  lessons  give  each  pair  of  pupils  a  couple  of  worms 
in  a  wet  saucer  covered  with  a  piece  of  glass,  as  some 
will  be  afraid  to  handle  the  worms  enough  to  keep  them 
in  the  saucer. 

1.  Worm. — Shape  ?  Color  ?  Parts  ?  (Many  rings  or 
joints.) 

2.  Skin.— How  does  it  feel  ?  Are  the  rings  all  equal  ? 
(Girdle.) 

3.  Head.— Has  the  worm  a  head  end  ?    Which  is  it  ? 
How  distinguished  from  the  tail  ?     (Nearest  girdle.) 

*  Kingsley,  Riverside  Nat.  His.,  vol.  i,  p.  270. 


74  SYSTEMATIC  SCIENCE  TEACHING. 

Where  is  the  mouth  ?  (On  the  underside  of  the 
head.) 

Can  other  organs  be  seen — eyes,  ears,  etc.  ?     (No.) 

4.  Where  does  the  worm  live  ?    (In  the  earth.) 

How  does  it  make  its  hole  ?  (Eats  a  hole,  or  pene- 
trates by  making  its  head  very  slender  and  inserting  it  in 
some  crack  and  then  swelling  out  and  pushing  the  earth 
aside.)  Which  must  it  do  in  compact  soil  ?  (Eat.) 
What  can  it  do  in  loose  soil  ? 

5.  How  does  it  move  ?  (See  backward-pointed  bristles 
on  underside,  and  note  how  in  climbing  the  smooth  side 
of  a  dish  it  hangs  on  with  its  mouth  by  sucking.) 

6.  What  does  it  eat?     (Earth,  decaying  leaves,  etc.) 
What  does  it  eat  earth  for  ?     (The  minute  plants,  eggs, 

animals,  etc.,  in  it.) 

Who  has  noticed  little  piles  of  fresh  earth  about  the 
garden  or  walks  ? 

These  are  called  worm  casts.  Are  there  many  of 
them? 

Can  you  think  of  any  benefit  from  all  this  earth 
brought  up  ?     (Keeps  changing  the  soil  for  plants.) 

How  do  the  many  holes  and  soft  places  where  the 
filled-up  holes  were  aid  plants  ?  (Make  easy  places  for 
roots  to  penetrate.) 

Suppose  a  lot  of  clam  shells  or  bones  lay  on  soil  where 
worms  were,  what  would  slowly  happen  ?  (Sink  from 
the  earth  taken  from  underneath  and  gradually  be  covered 
up  by  castings.) 

How  would  this  help  ?  (Hide  the  bones,  etc.,  place 
them  where  plants  could  feed  on  them,  and  level  the 
ground.) 

7.  When  do  worms  feed?    (At  night.) 

Have  they  any  way  of  preparing  food  for  themselves  ? 
(Pull  leaves  into  their  burrows.) 

Do  they  seem  to  have  the  power  to  choose  among 
leaves  ? 


ANIMALS.  75 

Do  they  seem  able  to  select  the  best  way  to  pull  a 
leaf  in  ? 

Do  worms  seem  to  feel  a  jar  to  the  earth  ? 

Do  they,  when  out  at  night,  notice  a  light  ? 

When  alarmed  by  a  jar  or  by  light,  what  do  they 
do  ?     (Quickly  withdraw  into  burrows.) 

Some  day  you  must  read  Mr.  Darwin's  book  about 
these  wonderful  animals. 

The  Starfish. 

I  have  never  had  any  but  dried  specimens  to  use, 
and  can  give  no  advice  about  the  use  of  live  ones. 
Provide  one  of  some  cheap  variety  for  each  pair  of  pu- 
pils.   The  main  point  to  develop  is  the  radiate  structure. 

1.  Parts?     (Arms  and  disk.) 

2.  How  many  arms?    How  arranged  ?    (Radiate.) 
Upper  side  ?    Lower  side  ?     (Stomach  extends  along 

the  grooves  in  the  arms.) 

The  rows  of  little  knobs  on  either  side  are  the  tube 
feet,  which  end  in  sucking  disks.  By  these  the  live  star- 
fish can  fasten  an  arm  on  to  anything  and  draw  itself  up 
to  it. 

Has  it  a  head  and  a  tail  ?    An  above  and  below  ? 

3.  The  mouth  is  in  the  center  of  its  underside,  and 
the  starfish  has  a  very  peculiar  way  of  feeding.  It  turns 
its  stomach  out  of  its  mouth  on  to  the  food  and  absorbs  it. 

4.  Where  do  starfish  live?  (In  the  salt  water  of  the 
sea.) 

5.  Has  it  an  outside  or  inside  skeleton  ?  What  is  it 
made  of  ?     (Carbonate  of  lime.     Test  some  bits  in  acid.) 

Has  it  two  symmetrical  (like)  halves  ? 

The  Coral 

Have  fragments  of  white  coral  for  the  pupils,  and  add 
such  help  as  possible  from  pictures. 

1.  Where  did  these  come  from  ?    (Sea  bottom.) 


76  SYSTEMATIC  SCIENCE  TEACHING. 

Of  warm  or  cold  seas  ?  (See  some  Physical  Geog- 
raphy— warm  seas.) 

Where  are  the  coral  reefs  located  ?  (In  ocean  and 
along  continents.) 

See  if  any  reefs  are  near  the  mouths  of  rivers.     (No.) 

2.  Examine  your  fragment  and  tell  me  if  it  is  stone. 
Why  not  stone  ?    (Has  regular  structure.)     Drop  a 

bit  in  acid. 

What  is  it  made  of  ?    (Lime  and  COa.) 

What  other  things  made  of  the  same  have  we  studied  ? 
(Eggshell,  crayfish  shell,  snail  and  clam  shells,  and 
starfish  skeleton.) 

How  were  all  these  made  ?  (They  grew  as  part  of 
some  animal.) 

So  it  is  with  the  coral.  It  is  the  hard  part,  skeleton, 
of  the  coral  animal,  very  many  of  which  usually  live 
together.  Each  little  pit  on  your  pieces  was  where  one 
lived. 

Are  the  animals  in  the  pits  now  ?    (No.) 

3.  Here  are  some  pictures  of  the  animals  as  they  look 
when  alive. 

Where  is  the  mouth  ?     (In  center  of  upper  side.) 
How  are  the  tentacles  arranged  ?    (In  a  circular  fringe 
around  it.) 

Of  what  use  are  these  ?     (To  catch  food.) 
How  do  they  hold  the  prey,  being  so  smooth  and 
slippery  ?     (All  along  the  tentacles  are  wonderful  little 
stinging  cells,  which  seem   to    paralyze  the  prey ;   the 
tentacles  then  convey  the  food  to  the  mouth.) 

Where  does  the  lime  come  from  ?    (The  food  it  eats.) 
As  to  number,  are  they  in  sixes,  or  eights  ?     (Six  or 
multiples  of  six.) 

4.  Examine  the  little  pits  where  the  coral  animals 
lived. 

What  do  you  notice  ?  (Little  plates  of  coral.)  Are 
all  these  equal  ? 


ANIMALS.  Y7 

How  are  these  arranged  ?    (Around  the  outside.) 

How  many  are  there  ?  Is  the  number  divisible  by- 
six,  or  eight  ?     (Six.) 

How  does  the  coral  resemble  the  starfish  ?  (Organs 
arranged  in  a  circle.) 

We  call  such  an  arrangement  radiate. 

The  Sponge. 

Provide  small  ones,  with  distinct  and  well-formed 
openings  at  the  top.  Go  or  send  to  some  wholesale  drug- 
gist, where  a  lot  of  good  specimens  can  be  cheaply  had. 
Eead  in  preparation  Professor  Hyatt's  Commercial  and 
Other  Sponges. 

1.  General  shape?     Color? 

3.  What  is  it  composed  of  ?     (Tough,  homy  fibers.) 

This  is  the  skeleton  of  the  sponge.  When  alive  it 
looks  much  like  a  piece  of  liver  growing  on  the  rocks  at 
the  bottom  of  warm  seas.  These  are  gathered  by  divers 
or  by  sponge  fishers  with  rakes  and  forks.* 

Read  to  the  class  what  Professor  Hyatt  tells  about  the 
gathering  and  preparing. 

Why  is  one  side  of  the  sponge  cut  ?  (Where  it  was 
separated  from  the  rock  or  larger  sponge.) 

3.  Each  of  these  liverlike  masses  is  a  whole  colony 
of  animals  living  together  like  the  people  in  a  city. 

What  in  the  skeleton  corresponds  to  the  streets  ? 
(Tubes.) 

Yes,  and  these  tube  streets  are  lined  with  groups  of 
little  animals. 

What  fills  these  tubes  in  life  ?    (Sea  water.) 

This  is  drawn  in  through  fine,  strainerlike  holes — 
where  ?    (Sides.) 

As  it  passes  along  the  tubes  the  minute  animals  and 

*  See  illustrations  in  Riverside  Nat.  His.,  vol.  i,  cr  Hyatt's 
Science  Guide,  No.  III. 


78  SYSTEMATIC  SCIENCE  TEACHING. 

plants  it  contains  are  seized  for  food  by  the  little  ani- 
mals, and  then  the  water  is  emptied  out  through  a  few- 
large  openings — where  ?     (At  the  top.) 

Now  examine  carefully  the  bases  of  your  specimens, 
and  tell  me  whether  your  specimen  is  a  whole  sponge, 
just  as  it  came  off  the  rock,  or  a  cut-off  branch  of  a  large 
one.  (Base  of  whole  sponge  will  have  few  holes,  and 
contain  bits  of  rock  or  shell,  while  a  branch  will  show 
the  large  tubes  and  no  rock.) 

4.  What  do  you  notice  more  about  these  skeletons  ? 
(Elastic,  soak  up  a  great  deal  of  water,  and  then  are  soft 
and  delicate.) 

5.  Show  pictures  of  or  draw  on  board  the  curious  fla- 
gellate cells  which  seem  the  individuals  of  the  sponge 
colony,  and  review  the  way  they  feed. 

Have  these  little  cell-animals  any  eyes,  ears,  etc.  ? 
(No.) 

Simple  as  these  are,  there  are  yet  simpler  and  lower 
ones,  but  these  we  can  not  study  now,  and  this  ends,  for 
the  present,  our  lessons  on  animals. 

Review. — None  desirable. 

Material. — Should  be  sorted,  replaced,  and  put  away 
in  boxes,  so  that  the  hand  can  be  at  once  placed  upon 
what  may  be  wanted  again. 

The  next  step  in  Animals  will  be  XXIX— Winter 
Quarters  of  Animals. 


STEP  XXVIII.— PLANTS. 
Their  Relations  to  Surroundings. 

Object. — To  widen  and  increase  the  pupils'  acquaint- 
ance with  plants. 

To  review,  in  other  relations,  past  lessons  along  all 
lines. 

To  aid  in  geography. 

To  prepare  for  future  work. 

Time. — Autumn  of  the  year.  Of  the  day,  at  the  close 
of  school,  when  all  other  classes  can  be  dismissed  and 
more  freedom  be  allowed. 

The  number  of  lessons  will  be  about  thirty,  of  fifteen 
to  twenty  minutes  each. 

Material. — Little  or  none  is  needed,  although  a  wise 
and  observing  teacher  will  gradually  gather  a  store  of 
specimens  to  illustrate,  which  to  the  gatherer  will  be 
valuable. 

Preparation  of  the  Teacher.— Go  through  the  lesson 
carefully  and  test  everything  possible.  If  this  is  begun 
in  the  previous  spring  and  continued  through  the  sum- 
mer many  valuable  things  will  be  seen  and  interesting 
discoveries  made.  Should  the  school  have  a  garden  plot, 
a  class  that  has  had  the  lessons  might  superintend  the 
carrying  out  of  many  test  cultures  by  the  class  that  is  to 
have  the  lessons  in  the  fall.  In  case  the  school  has  no 
garden  the  teacher's  home  garden  might  become  the 
center  of  intensely  interesting  work.  No  one  fully 
grasps  these  things  who  has  not  seen  and  worked  over 
them.      For  books,   consult  physical    geographies    and 

79 


80  SYSTEMATIC  SCIENCE  TEACHING. 

physiological  botanies,  but  the  range  is  too  wide  to  be 
found  in  any  one  book,  unless  it  be  Kerner  and  Oliver's 
"Natural  History  of  Plants." 

The  Lessons. 

These  are  to  draw  out  what  the  pupil  has  learned 
through  experience  and  observation  oi  from  the  preced- 
ing lessons  on  minerals,  plants,  and  animals,  and  exhibit 
new  relations.  Hence,  tell  nothing  that  can  in  any  way 
be  drawn  out  by  question  or  experiment. 

The  steps  in  teaching  should  be  as  follows : 

a.  Introduce  the  point  to  be  considered  in  such  a  way 
as  to  have  it  clearly  before  the  class. 

b.  Find  what  ideas  the  class  may  already  have. 

c.  If  there  are  other  relations  which  they  have  not 
thought  of,  suggest  them  by  illustration,  experiment,  and 
question. 

d.  Let  all  conclusions  go  on  the  board  or  into  note- 
books, and  at  the  close  sum  up  all  about  the  point  in 
hand. 

e.  Promptly  pass  to  the  next,  and  have  the  progress 
steady.  More  interest  is  killed  by  a  dilatory  manner 
of  handling  the  subject  than  in  any  other  way  known  to 
me.  Very  dry  subjects  become  attractive  through  vigor- 
ous handling.  Hence,  do  not  begin  till  you  are  ready 
to  push  the  matter  to  a  close,  and  then  as  promptly  stop. 

1.  Sunlight. — What  do  plants  get  from  the  sun  ? 
(Light  and  heat.) 

How  does  light  affect  them  ?  * 

Some  open.  (Tulip,  poppy,  and  water  lily.)  Find 
others,  and  tell  us. 

Some  close.  (Morning-glory,  four-o'clock,  and  even- 
ing primrose.)     What  others  ? 

*  Let  the  class  think  of  the  morning  and  other  times  of  day, 
and  tell  what  they  can  of  all  the  things  that  the  sun  will  do  to 
the  plants,  and  illustrate  by  examples. 


PLANTS.  81 

Plants  turn  toward  the  light.  (Lupine  leaves  and  all 
window  plants.) 

Leaves  turn  green.  (This  is  apt  to  be  all  the  class  will 
think  of.)  Now  suggest,  Who  knows  the  oxalis  or  white 
clover  ?  See  how  the  leaflets  are  arranged  to-night,  and 
again  to-morrow  morning.     (They  wake  up  !) 

Do  all  leaves  "sleep"  ? 

Smell  of  squash,  mignonette,  four-o'clock,  and  other 
flowers  to-night,  and  again  to-morrow  before  coming  to 
school.  Is  there  any  difference  in  the  odor  ?  (Squash 
and ?  were  stronger  in  the  morning.) 

There  is  another  and  very  important  thing  which  sun- 
shine makes  leaves  do.  Here  are  several  fruit  jars,  with 
good  rubbers  to  close  them  securely.  In  each  I  will  pour 
two  cm.  of  water.  Here  are  several  bits  of  candle  on 
wires.  John,  Kate,  Mary,  and  Sam  may  come  and  help 
me  light  the  candles  and  hold  them  in  the  jars  till  they 
go  out. 

What  have  the  burning  candles  made  in  the  jars  ? 
(CO,.) 

If  I  light  them  again  and  lower  into  this  COa  ?  (Will 
go  out.) 

We  will  try  it  and  see.    Yes,  they  do  go  out. 

Now,  in  each  jar  I  will  stand  these  sprigs  of  mint  (or 
other  plant  which  will  keep  fresh  in  water)  and  screw  on 
the  tops  tightly  and  set  in  the  sun  for  two  or  three 
days. 

What  will  the  growing  leaves  do  ?  (Eat  up  the  COa.) 
We  will  see. 

Where  must  I  have  the  leaves  ?  (In  the  sunshine.) 
How  can  I  prove  sunshine  is  needed  ?  (Put  one  in  the 
dark.) 

We  will  do  this,  and  at  the  end  of  the  time  how  can 
we  test  ?     (Try  the  candles  again.) 

While  waiting  let  us  try  another  experiment.  Here 
are  sprigs  of  the  same  plants  in  the  fruit  jars.  I  will  fill 
7 


82  SYSTEMATIC  SCIENCE  TEACHING. 

these  tumblers  with  cistern  water,  push  a  leafy  sprig  into 
each,  and  invert  them  in  these  saucers  and  set  in  the 
bright  sun.  What  happens  ?  (Bubbles  of  gas  come  off.)  * 
Move  into  the  shade  ?     (Gas  stops.) 

What  is  it  that  sunshine  makes  green  leaves  do  ? 
(Purify  the  air  by  removing  the  COa.)  Yes,  and  what 
besides  taking  in  the  COa  ?  (Give  out  gas.)  If  we  could 
test  this  gas  which  is  given  off  we  should  find  it  to  be 
oxygen,  just  what  we  need  to  breathe.  Where  does  the 
plant  get  it  ?     (From  the  COa.) 

Review  Sunlight.  In  this  manner  take  up  the  follow- 
ing points : 

2.  Darkness.— How  does  this  affect  plants  ? 
Some  open.     (Four-o'clock,  evening  primrose.) 
Some  close.     (Marigold,  daisy,  crocus,  tulip.) 
Leaves  sleep.     (Oxalis,  lupine,  white  clover.) 

Some  odors  are  strongest.  (Four-o'clock,  night-bloom- 
ing cereus.) 

COa  is  not  taken  in.     (Test  jar  in  the  dark.    See  1.) 
Oxygen  is  not  given  off.     (See  1). 

3.  Heat. — How  does  this  affect  plants  ? 
Causes  rapid  growth. 

Water  passes  off  from  the  leaves. 
Kills  if  too  great. 

4.  Cold. — Checks  growth. 

Some  leaves  fold  to  keep  warm .     (Seed  leaves  of  radish, 

morning-glory,  four-o'clock.) 

Leaves  fall.     (All  deciduous  trees,  etc.) 

Buds  put  on  thick  scales.     (Hickory,  ash.) 

Tender  plants  die.    (All  in  temperate  zone.) 

Hard  seed  pods  or  husks  are  opened.     (Hickory  nuts, 

black  walnuts.)     (See  Sharp  Stones,  Step  XX.) 

Prepares  and  loosens  the  soil.     (See  Sharp  Stones.) 

*  See  Goodale's  Physiological  Botany,  p.  305,  for  suggestions 
about  this  experiment. 


PLANTS.  83 

5.  Air.— Supplies  the  CO2.  (See  Morning-Glory,  Step 
XXIII.) 

Eeceives  oxygen  from  the  leaves.     (See  1.) 

Receives  water  from  the  leaves.     (See  Morning-Glory.) 

6.  Wind.— Carries  pollen.  (Grasses,  pines.)  What 
others  ? 

Carries  odors.     (Rose,  heliotrope.) 

Scatters  seeds.     (Maple,  dandelion,  cotton  wood.) 

Changes  the  air. 

Injures  by  drying  too  much.* 

7.  Dew.— Moistens  the  leaves  and  ground.  (Benefits 
by  diminishing  evaporation  from  the  leaves  and  by  con- 
densation in  the  pores  of  loose,  dry  soil,  thus  greatly  help- 
ing in  dry  times.) 

Which  leaves  have  the  most,  those  held  horizontally, 
or  those  held  edgewise  or  vertically  ?  (See  oxalis,  white 
clover.) 

Which  the  most — hairy  or  smooth  leaves  ?    Why  ? 

Which  part  of  the  leaf  has  the  most  ?    (Tip.) 

Is  the  dew  on  the  upper  or  on  the  under  side  ?    Why  ? 

Does  it  form  under  the  shade  of  trees  and  bushy 
plants?    (Why  not?) 

8.  Rain. — Supplies  moisture  to  the  roots. 
Moistens  the  surface  (like  dew). 
Washes  off  dust,  etc. 

Softens  the  bud  scales  so  that  they  open  easily. 
Softens  the  soil  for  roots  to  penetrate  and  seedlings  to 
emerge. 

*  Dry  winds  often  so  injure  the  stigmas  or  pollen  grains  of 
flowers  just  ready  for  fertilization  as  to  cause  a  "  short  crop"  of 
grain,  cherries,  etc.  On  the  other  hand,  a  very  still  time,  when 
corn  is  in  bloom,  prevents  the  stirring  of  the  silk,  and  the  falling 
pollen  fails  to  reach  the  long  styles  and  stigmas  in  the  center,  so 
that  there  is  a  long  "  tip  "  of  undeveloped  ovules  at  the  end  of 
the  ear. 


84  SYSTEMATIC  SCIENCE  TEACHING. 

Wastes  pollen  and  nectar. 

How  do  the  following  plants  avoid  this  waste  ? 

Portulaca  and  common  purslane  ?  Petunia  ?  Honey- 
suckle ?    Daisy  or  dandelion  ?    Sunflower  or  oxeye  daisy  ? 

(Some  of  these  do  not  open,  others  are  drooping  bells, 
others  have  fine  tubes  into  which  the  drops  can  not  get 
because  of  the  imprisoned  air.) 

Forests  increase  the  rainfalL 

9.  Drought. — How  do  plants  manage  in  a  very  dry 
time  ? 

The  roots  strike  downward.  (Illustrates  the  need  of 
deep  plowing  and  digging.) 

Leaves  droop  and  curl,  so  as  to  protect  themselves. 
(Cornfields,  etc.) 

Leaves  fall  off  to  prevent  stem  being  exhausted. 

Where  it  is  always  dry  ?  (Cacti.)  Leaves  are  re- 
duced to  little  brown  spines,  and  the  green  stem  takes 
their  place. 

Deserts  ?  (So  dry  nothing  can  grow.  Prevent  the 
spread  of  plants.) 

10.  Brooks  and  Rivers.— What  have  these  to  do  with 
plants  ? 

Rub  rocks  to  pieces  and  make  soil.  (See  Sharp 
Stones.) 

Make  rich  river  bottoms  and  deltas.  (Show  Nile, 
Mississippi,  and  Ganges  on  map.) 

Water  rainless  tracts.  (Nile  and  western  United 
Stfiites;  see  map.) 

Transport  seeds  and  plants.* 

Are  kept  at  even  flow.    (See  11.) 

11.  Soil— What  kinds  can  you  think  of?  (Rich, 
sandy,  rocky,  etc.) 

How  do  plants  thrive  in  fertile  soil  ? 

1.  Grow  rank  and  large.     (Rich  garden.) 

*  Natural  History  of  Plants,  ii,  p.  846  ff. 


PLANTS.  85 

2.  Are  late  in  blooming  and  fruiting.  (Vegetables  or 
grain  on  very  rich  soil  are  apt  to  be  cut  by  frost  before 
maturing.) 

How  on  sandy  soil  ?  (Dwarfed ;  bloom  and  fruit  early 
but  sparingly.) 

(Gardeners  who  want  early  tomatoes,  melons,  or  corn, 
are  careful  not  to  have  the  soil  very  rich.) 

How  do  plants  affect  soils  ? 

Keep  loose  sands  from  drifting.  (Beach  grass  and 
mangrove.) 

Strengthen  the  banks  of  rivers.     (Willows,  alders,  etc.) 

Break  rocks.     (See  Step  XX.) 

Make  the  soil  black.    (Decay  of  leaves,  etc.) 

Exhaust  the  fertility.  (Tobacco  lands  of  Virginia, 
etc.,  and  "worn-out"  lands  everywhere.)  An  interesting 
experiment  is  to  weigh  a  dry  cigar  or  other  dry  leaves 
and  then  burn  in  a  clean  open  dish  and  find  the  per 
cent  of  ash  by  weighing.  This  gives  some  idea  of  the 
enormous  drain  tobacco  and  other  leaf  crops  are  to  the 
soil. 

Enable  the  soil  to  hold  much  water.  (The  spongelike 
mass  of  decayed  leaves  in  a  forest  holds  immense  quan- 
tities of  water,  and  after  a  rain  permits  it  to  gradually 
drain  away,  thus  preventing  the  floods  which  rivers  in 
unwooded  countries  are  subject  to,  and  keeping  the 
springs  and  streams  at  a  steady  flow  ;  see  10.) 

12.  Gravitation.— How  does  this  aft'ect  plants  ? 
Causes  roots  to  strike  downward. 

Causes  seeds  to  fall  where  they  can  grow. 

13.  Mountains. — Have  they  any  effect  on  plants  ? 
Prevent  the  spread  of  plants. 

Shelter  those  in  the  valleys. 

Raise  those  on  top  into  a  higher,  drier,  and  colder 
climate. 

Show  the  class  some  physical  geography  chart,  or  rep- 
resent it  on  the  board,  showing  the  effect  of  mountains 


86  SYSTEMATIC  SCIENCE  TEACHING. 

in  a  tropical  climate.  Note  the  kind  of  plants  (palms, 
tree  ferns,  etc.)  at  the  base ;  next  the  hard- wooded  trees 
and  grains  of  the  temperate  middle  section ;  then  the 
cone-bearing  trees,  etc.,  of  the  next  belt,  gradually  dwarf- 
ing and  giving  way  to  low  willows,  and  at  last  mosses 
and  lichens,  which  end  in  everlasting  snow. 

14.  Latitude.— What  is  ''latitude"?  (See  Step 
XXII.) 

Where  does  the  sun  shine  perpendicularly  ?  What 
zone  do  we  call  it  ? 

What  is  the  effect  on  the  plants  that  live  there  ?  (Rank 
and  large.) 

Where  are  the  nights  longest  ?  What  is  this  region 
named  ? 

How  do  plants  thrive  with  so  little  sun  ?  (Dwarfed 
or  none.) 

Why  is  the    middle    section  called   the    "temperate 
zone  "  ? 

How  about  the  plants  where  warm  and  cold  seasons 
alternate  ? 

What  does  the  gradation  from  the  huge  and  rank 
plants  of  the  tropics  to  the  barrenness  of  the  arctic  zone 
remind  you  of  ?     (Mountain-sides.) 

15.  Time. — How  does  length  of  life  affect  a  plant  ? 
Those  with  soft  tissues,  dying  down  each  year,  we 

call  ?     (Herbs.) 

Those  with  woody  tissues  ?     (Shrubs  or  trees.) 

Those  living  one  year  are  called  ?  (Annuals.)  Name 
some.     (Beans,  etc.) 

Those  living  two  years  ?  (Biennials.)  Name  some. 
(Carrot,  etc.) 

Those  living  several  years  ?  (Perennials.)  Name 
some.     (Oak,  etc.) 

What  does  the  continued  growth  of  perennials  give 
us  ?  (Size  and  beauty  of  trees  and  shrubs  and  wood  for 
building,  fires,  etc.) 


PLANTS.  87 

16.  The  Sea.— How  does  this  affect  plants  ? 
Nourishes  some.     (Seaweeds.) 

Destroys  land  plants  by  its  salt  water. 

Carries  some  seeds  and  fruits  to  new  islands  and 
lands.* 

What  fruits  do  you  know  of  seemingly  able  to  stand 
sea  water  ?    (Cocoanut,  date,  breadfruit.) 

Is  the  unfrozen  ocean  as  cold  as  the  land  in  winter  ? 
(No.) 

As  warm  in  summer  ? 

What  way  is  there  for  this  heat  or  coolness  to  be  car- 
ried to  the  land  ?     (Winds.) 

Suppose  these  blow  off  shore  f 

How  if  they  blow  landward  most  of  the  time  ?  f 

How  will  oceans  affect  the  plants  near  which  they 
are  ? 

How  about  the  climate  of  islands  ?    (Milder  and  even.) 

17.  Other  Plants. — Will  plants  growing  near  together 
help,  or  hinder,  each  other  ? 

What  do  plants  take  from  the  soil  ?  (Earth  food.) 
(See  Morning-Glory.) 

Will  it  help,  or  hinder,  for  others  to  grow  in  the  same 
soil? 

How  many  reasons  can  you  think  of  why  weeds  are 
injurious  ?    (First,  look  badly ;  second,  drain  the  water 

*  Wallace,  Island  Life,  pp.  257-259. 

f  Show  the  class  charts  or  maps  of  the  distribution  of  heat 
or  vegetation,  and  lead  them  to  observe  the  greater  warmth  and 
consequent  extension  toward  the  poles  on  the  western  sides ;  the 
downward  curve  in  the  center  of  great  land  masses  and  the  in- 
termediate condition  on  the  eastern  shores,  where  the  winds  from 
the  ocean  are  less  persistent  and  do  not  affect  the  climate  far 
within  the  interior.  Illustrate  this  fully  on  charts  and  globes, 
and  the  "  seed  thoughts"  planted  in  this  connection  will  develop 
into  a  clear  comprehension  of  this  important  subject. 


88  SYSTEMATIC  SCIENCE  TEACHING. 

from  the  soil ;  third,  exhaust  the  needed  "  earth  food  "  ; 
fourth,  shade  the  plants  we  want,  and  prevent  the  sun 
doing  its  work.) 

Why  do  farmers  find  it  best  not  to  plant  t]^e  same 
crop  on  a  piece  of  land  for  a  number  of  successive  years  ? 
(See  11,  Soil.) 

How  does  the  dandelion  make  room  for  itself  in  the 
grass  ? 

How  would  the  morning-glory  interfere  with  currant 
bushes  ? 

Why  does  the  broad-leaved  and  quick-growing  buck- 
wheat "  kill  the  weeds  "  ? 

Why  does  a  field  of  "  timothy "  grass  so  soon  "  run 
out "  and  become  redtop  ? 

Fayal,  an  island  in  the  Azores,  was  named  from  a 
small  tree  called  the  Faya,  which  grew  abundantly  and 
supplied  excellent  fuel.  Some  one  brought  to  the  island 
another  small  tree,  the  Pittosporum,  for  the  sake  of  its 
beautiful,  glossy  leaves  and  clusters  of  fragrant  white 
flowers,  followed  by  orange-colored  pulpy  fruits.  This 
has  very  poor  wood  for  fuel,  and  yet  it  is  spreading 
everywhere  and  driving  out  the  better  Faya.  Why  ? 
(Birds  scatter  the  indigestible  seed.) 

The  sheep  sorrel  (Rumex),  which  reddens  so  many  pas- 
tures ;  the  bitter  oxeye  daisies,  which  dot  the  meadows ; 
the  plantain  (*' white-man Vfoot ")  of  our  lawns;  and  the 
mayweed  by  the  roadside,  are  other  examples  of  this 
struggle  for  life. 

On  the  other  hand,  let  some  of  the  pupils  cut  a  square 
foot  of  turf  from  a  pasture  with  a  close  sward,  and  others 
similar  areas  from  a  grain  field  or  cultivated  meadow 
where  one  kind  of  plant  alone  grows.  Shake  the  earth 
from  these,  and  find  in  each  case  : 

1.  How  many  plants  to  the  square  foot, 

2.  How  many  kinds  in  each  case. 

From  these  counts   (placed  in  tabular  form   on   the 


PLANTS.  89 

board)  the  class  will  almost  invariably  discover  that  dif- 
ferent kinds  of  plants  get  along  better  together  than 
many  of  one  kind.  Why  do  we  sow  a  mixture  of  several 
grasses  and  clover  if  we  want  a  thick,  green  lawn  ? 

Why  do  farmers  say,  "  The  worst  weed  in  a  cornfield 
is  corn  "  i  The  same  might  be  said  of  any  crop  which 
stands  too  thick. 

How  do  plants  manage  to  spread  their  area  of  growth  ? 

The  balsam,  tame  or  wild  ?     (Snaps.) 

The  dandelion  ?     (Wind  carries.) 

The  burdock  ?     (By  its  hooks.) 

The  pea  or  bean  ?     (Carried  for  food.) 

The  raspberry  ?  The  strawberry  ?  (Two  ways  :  eateb 
by  birds  and  spread  by  "runners,"  etc.) 

The  apple  ?     (Eaten  by  animals.) 

The  chestnut  or  other  nut  ?      (Eaten  by  squirrels,  etc.) 

Corn  or  other  grain  ?  (Eaten  by  man,  squirrels,  and 
mice.) 

The  class  can  now  readily  see  the  use  to  the  plant  of 
its  edible,  colored,  fragrant,  hooked,  plumed,  winged,  and 
snapping  fruits  and  seeds.  Also  why  many  seeds  are  so 
hard  and  indigestible.     To  sum  up  this  point : 

Plants  are  continually  struggling  with  each  other  for 
food,  etc. 

Those  of  the  same  kind  make  worse  neighbors  than 
those  that  use  different  elements  of  the  soil  for  food. 

Plants  secure  a  scattering  of  their  seed  by  aid  of  their 
colored  fruits,  hard  seed,  wings,  hooks,  etc. 

Plants  also  help  each  other. 

How  does  a  tree  help  a  vine  ? 

How  do  the  different  corn  plants  in  a  field  aid  each 
other  ?     (Pollen.) 

Half  of  the  willow  "  pussies  "  have  no  stamens.  How 
do  they  get  pollen  ?     (From  another  bush.) 

What  will  be  the  result  of  a  stalk  of  red  corn  growing 
among  yellow  corn  ?      (The  yellow  ears  will  have  red 


90  SYSTEMATIC  SCIENCE  TEACHING. 

kernels  scattered  on  the  ears,  or  have  striped  "  calico  "  ears 
of  corn.    We  call  this  "crossing.") 

Can  you  find  evidences  of  crossing  in  other  flowers, 
fruits,  or  seed  ? 

18.  Insecta* — Think  of  all  the  ways  you  can  in  which 
plants  and  insects  affect  each  other.  First,  How  do  plants 
affect  insects  by 

Odors  ?  (Attract.)  When  are  odors  usually  strong- 
est ?    (See  Step  XVII.) 

Colors  ?  (Attract.)  What  color  is  most  common 
among  night  bloomers  ?    (White.)     Why  ? 

Shape  ?  (Guides  and  prevents  the  nectar  being 
taken  without  the  pollen  being  carried.)  (See  Morning- 
Glory.) 

Separation  of  stamens  and  pistils,  making  insects 
carry  the  pollen  from  one  flower  to  the  stigmas  of  an- 
other. 

Nectar  ?     (Rewards  the  visiting  insects.) 

All  this  is  friendly  and  mutually  helpful.  Against 
injurious  insects  or  those  not  helpful,  we  find  t 

Hairs.  (Place  ants  or  small  beetles  on  hairy  plants, 
and  observe.) 

Sticky  secretions.  (Place  small  insects  on  tomatoes, 
petunia,  or  Pentstemon.) 

Color.  (Dull  yellows  are  mostly  avoided  by  beetles, 
but  visited  by  the  helpful  flies,  bees,  and  butterflies.)  J 

Offensive  odors.  (Mint,  geranium,  musk  plant,  etc.) 
Are  such  plants  eaten  by  many  insects  ? 

Strong  taste.  (Observe  sweet  fern,  sorrel,  rhubarb,  and 
green  fruits.) 

Hard,  woody  leaves.  (Do  caterpillars  like  young,  or 
old,  leaves  best  ?) 

*  Natural  History  of  Plants,  ii,  p.  152  ff. 
f  Natural  History  of  Plants,  ii,  p.  231  ff. 
X  See  Goodale,  p.  455,  or  Coulter's  Plant  Relations,  p.  136. 


PLANTS.  91 

Structure  of  flowers : 

1.  Throat  closed^  and  opening  only  with  the  weight  of 
a  heavy  insect.     (Snapdragon,  etc.) 

2.  Throat  a  narrow  tube,  where  only  insects  with 
long  tongues  can  reach  the  nectar.     (Red  clover,  etc.) 

3.  Throat  filled  by  the  stamens  and  pistils.  (Phlox 
and  petunia.) 

Second,  How  do  insects  affect  plants? 

Carry  pollen,  and  so  cause  seed  to  grow. 

Cross  fertilize,  the  pollen  of  one  plant  being  carried 
to  others  of  the  same  kind.  (Squash,  willows,  orchids, 
etc.)    This  gives — 

1.  Stronger  plants.  (Morning-glory,  as  85.84  is  to  66.02 
inches.)  * 

2.  More  seed.     (Morning-glory,  as  100  is  to  51.)  * 

3.  New  varieties.     (Mixed  corn,  morning-glories,  etc.) 
Eat  them.     (Grasshoppers,  potato   beetles,  rose   bee- 
tles, etc.) 

Lay  eggs  on  them,  causing — 

1.  Galls.     (Oak  "  apples,"  golden-rod  gall,  rose  galls.) 

2.  Boring  larvae.  (Currant,  raspberry,  and  apple-tree 
borers.) 

3.  Sucking  insects.     (Plant  lice  and  squash  bugs.) 

4.  Eating  larvae.  (Caterpillars  of  tomato  and  Virginia 
creeper,  and  slugs  of  cherry  and  rose.) 

(Cutworms,  which  eat  young  plants  off  at  the 
ground.) 

Destroy  injurious  insects.  (Ichneumon  and  lady 
beetle.) 

19.  Birds.— Plants  help  the  birds  by— 

1.  Food.  (Class  tell  of  different  foods  and  what  birds 
eat  them.) 

2.  Shelter.     (Where  and  when  ?) 

*  See  Darwin's  experiments ;  and  Goodale's  Physiological  Bot- 
any, p.  448. 


92  SYSTEMATIC  SCIENCE  TEACHING. 

3.  Screens  for  their  nests.     (Expand  this.) 

4.  Material  to  build  nests.  (What  are  these  mate- 
rials ?) 

5.  By  purifying  the  air  from  COa  and  restoring  the 
oxygen. 

Birds  repay  the  plants  by— 

1.  Carrying  seeds  to  new  places.*  Pittosporum  in  the 
Azores  (17). 

How  do  "  thimble  berries  "  (black  raspberries)  come  to 
be  so  common  by  fences  and  walls  ?  My  garden  has 
much  knotweed,  with  hard,  shiny  black  seeds.  Why 
do  patches  of  it  keep  coming  up  in  the  grass  of  my  front 
lawn  ?     (Hens.) 

Pigeons  swallow  acorns  and  other  large  fruits  whole, 
and  then  feed  their  young  by  raising  the  softened  food 
from  the  crops  and  placing  it  in  their  mouths.  How 
might  seeds  and  fruits  be  easily  started  in  new  places  ? 
Mistletoe,  t  See  account  of  the  spread  of  the  nutmeg  in 
the  Spice  Islands.  J 

2.  Eating  injurious  insects.  Each  part  of  the  tree  and 
each  place,  high  or  low,  has  its  particular  set  of  birds  to 
attend  to  this  :  as 

In  the  ground.     (Scratching  hen,  etc.) 
On  the  ground.     (Hen,  brown  thrush,  robin,   duck, 
etc.) 

On  bark.     (Nuthatch,  brown  creeper,  etc.) 

Under  bark.     (Woodpeckers.) 

Leaves  and  buds.     (Warblers,  etc.) 

Flowers.     (Humming  birds.) 

Fruits.     (Blue  jay,  woodpecker,  cherry  bird,  robin.) 

In  the  air.     (Swift,  swallow,  and  pewee.) 

3.  By  food.    COa  is  constantly  given  off. 

*  Wallace,  Island  Life,  chap.  v. 

t  Nat.  Hist,  of  Botany,  i,  p.  205  ff. 

X  Wallace,  Malay  Archi.,  pp.  288  and  418. 


PLANTS.  93 

The  guano  beds  off  Peru  are  vast  deposits  of  the  drop- 
pings of  sea  fowl. 

Hen  manure  is  also  very  rich  food  for  plants. 
20.  Animals.— How  do  plants  help  these  ? 

1.  By  food.    What  is  eaten  ?    By  what  animals  ? 

2.  By  shelter.  (When,  where,  and  how  ?)  Storm  and 
winter.     Hollow  trees,  under  branches,  etc. 

3.  By  floating  them  to  new  places.    . 

Trees  are  frequently  torn  away  from  the  banks  of  a 
river  by  freshets.  What  might  happen  to  insects  or 
borers  on  them  ? 

Suppose  a  sudden  flood  should  sweep  a  nest  of 
squirrels  or  a  snake  away  on  the  log  ? 

4.  By  purifying  the  air  from  COa  and  restoring  its 
oxygen. 

How  do  animals  help  plants  ? 

1.  They  carry  seeds  to  new  places. 

Burrs,  etc.,  on  sheep  or  in  the  tails  of  animals. 

Indigestible  seeds. 

Grain  and  nuts.     (By  mice,  chipmunks,  and  squirrels.) 

2.  Animal  waste  is  food  for  plants. 

COa  is  constantly  given  off.  What  part  of  the  plants 
takes  it  in  ? 

Compost  from  stables  is  so  valuable  for  crops  as  to  be 
constantly  employed. 

"  Bone  dust "  is  the  ground-up  bones  of  dead  animals. 

"  Blood-and-bone "  fertilizer.  Its  name  indicates  its 
origin  in  the  refuse  of  slaughterhouses.  (Fine  for 
crops.) 

"  Superphosphate  "  is  prepared  from  animal  remains. 
That  from  South  Carolina  is  the  remains  of  extinct 
animals. 

Bones  and  other  remains  of  animals  buried  where  the 
roots  of  grapevines  or  other  plants  can  reach  them  soon 
become  covered  with  a  net  of  feeding  roots. 

The  niter  deposits  and  "  bat  earth  "  of  Mammoth  and 


94  SYSTEMATIC  SCIENCE  TEACHING. 

other  caves  are  rich  in  plant  foods  and  formed  from  the 
droppings  of  the  multitude  of  bats  that  swarm  in  them. 

Guano  is  obtained  from  rainless  islands  (Chincha, 
Lobos,  etc.),  which  have  been  the  roosting  places  of  sea 
birds  for  many  years. 

The  menhaden  and  other  abundant  fish  have  long 
been  caught  to  make  an  artificial  guano.  The  oil — of  no 
value  to  plants — is  first  expressed  and  the  remaining 
bones,  skins,  etc.,  ground  up. 

How  do  plants  defend  themselves  against  animals  ? 

1.  Roots  and  tubers  are  buried  in  the  ground.  (Give 
examples.) 

2.  Many  stems  and  leaves  become  too  woody  and  dry 
to  be  agreeable  food. 

3.  Some  arm  themselves  with  spines  or  thorns. 
(Wild  apple,  Osage  orange,  rose,  and  especially  the  much- 
exposed  cacti,  etc.,  of  deserts.) 

4.  Many  leaves  are  pungent  (mints,  geranium,  etc.) ; 
bitter  (oxeye  daisies  and  bulbous  buttercup  make  cows 
sick)  ;  sour  (animals  avoid  sheep  sorrel — Rumex — and 
rhubarb)  ;  wooly  (mullein  is  seldom  eaten)  ;  prickly  (this- 
tles in  all  their  variety) ;  poisonous  (castor  bean,  olean- 
der) ;  or  stinging  (nettle). 

5.  Flowers.  Besides  the  devices  above  referred  to, 
flowers  at  times  hide  themselves  under  the  leaves,  as  in 
several  of  the  violets,  where  the  showy  flowers  of  spring 
are  succeeded  by  many  greenish  flowers  near  the  roots 
which  produce  seed  all  summer. 

6.  Fruits  defend   themselves  while  growing  by  be- 
ing- 
Sour.     (Apples,  peaches,  etc.) 

Bitter.     (Persimmon  and  black  walnut.) 
Hard-shelled.    (Hickory  nut  and  pecan.) 
Prickly.     (Chestnut  burr,  wild  gooseberry.) 
Hidden.     (Many  fruits  bend  down  close  to  the  ground 
soon  after  setting — white  clover,  peanut.) 


PLANTS.  95 

Green  and  leaflike  in  color,  the  attractive  coloring 
only  appearing  when  the  seeds  are  ripe  enough  to  be 
spread. 

This  must  close  this  interesting  subject. 

Much  more  might  be  added,  but  I  have  chosen  sam- 
ples of  the  more  interesting  and  familiar  points. 

Review. — None  is  needed  beyond  that  arranged  for  in 
the  succeeding  steps,  and  the  constant  application  of  all 
to  the  geography  and  reading  lessons. 

Prepare  for  the  next  step  in  Plants  by  arranging  with 
this  class  to  provide  supplies.  Plan  and  assign  each  his 
part,  and  keep  a  record  as  a  reminder  next  spring. 

The  next  piece  of  botanical  work  is  Step  XXXIV — 
Plants  in  Winter  Quarters. 


STEP  XXIX.— ANIMALS. 
In  Winter  Quarters. 

The  object  of  this  step  is  to  extend  the  acquaintance 
with  native  animals  through  a  study  of  their  winter  con- 
ditions, and  thus  introduce  ideas  of  the  "struggle  for 
life  "  due  to  environments. 

Time. — In  late  autumn,  when  animal  life  has  nearly 
disappeared,  the  studies  of  plant  relationships  will  have 
preceded  and  prepared  the  way. 

About  twenty  lessons  of  half  an  hour  each  will  be 
sufficient. 

Material — Previous  work  will  have  made  ready  for 
this  step,  and  it  only  remains  to  show  such  specimens, 
pictures,  skins,  or  stuffed  animals  as  shall  make  the  con- 
cepts of  the  children  clear  and  correct. 

Preparation  of  the  Teacher.— The  literature  of  this 
subject  is  so  scattered  and  fragmentary  as  to  render  ref- 
erences of  little  value  to  the  average  teacher.  State  and 
Government  reports  on  zoology  are  frequently  very  help- 
ful, while  personal  observation  is  especially  so,  and 
should  be  made  the  substantial  basis  of  the  work. 

What  follows  is  for  the  Central  United  States.  Teach- 
ers in  other  localities,  especially  North  or  South,  must 
vary  the  details  to  make  it  truthful  for  local  conditions. 
Having  reviewed  the  step,  decided  on  substitutes  (if  need 
be)  for  animals  here  named,  and  in  some  way  become  fa- 
miliar with  the  food  and  habits  of  those  selected,  write 
out  such  a  set  of  notes  as  it  is  expected  the  pupils  will 
keep. 

96 


ANIMALS.  97 

The  Lessons. — Each  pupil  should  have  a  notebook 
kept  especially  for  science  work,  6x3^  inches  in  size, 
opening  at  the  end  and  having  fifty  pages  of  good  paper. 

Use  both  sides  of  the  page,  but  do  not  crowd  the 
notes. 

It  is  best  to  use  a  page  for  each  animal. 

Introduce  the  subject  by  calhng  attention  to  the  dis- 
appearance of  animals,  birds,  and  insects  which  were  so 
abundant,  and  raise  the  questions.  Where  have  they  gone  ? 
Why? 

To  answer  these  questions  and  open  up  a  delightful 
subject  proceed  as  follows  : 

First.  Let  each  take  his  notebook,  and,  having  writ- 
ten the  title  of  the  lessons  in  ink  on  the  cover,  proceed  to 
make  a  list  of  all  the  wild  animals  he  knows  of  in  his 
section  of  the  country.  Encourage  some  attempt  at  clas- 
sification by  advising  each  child  to  put  in  classes  the 
names  of  animals  which  seem  to  resemble  each  other, 
and,  having  named  all  he  can  think  of,  leave  a  few  blank 
lines  in  order  that  additions  may  be  made. 

When  the  class  seems  to  have  exhausted  its  resources 
as  individuals,  make  a  count  and  see  who  has  thought 
of  the  most  names. 

Second  (probably  the  next  lesson).  Begin  to  compare 
notes,  that  each  may  have  the  aid  of  the  others.  Let 
pupil  No.  1  read  the  name  first  in  his  list.  If  it  is  that  of 
a  wild  animal  and  to  the  purpose,  advise  all  who  do  not 
have  it  to  add  the  name  to  their  list  of  the  same  kind. 
(If  of  a  domesticated  animal,  throw  it  out.) 

Then  let  pupil  No.  2  read  his  first  unread  name,  and 
so  continue  till  the  lists  are  exhausted. 

Questions  regarding  grouping  will  come  up  for  dis- 
cussion, but  this  is  not  the  place  to  teach  classification 
beyond  the  valuable  step  each  one  will  take  who,  decid- 
ing on  some  characteristic,  attempts  to  group  his  ani- 
mals under  it.  The  teacher  should  encourage  each  to 
8 


98  SYSTEMATIC  SCIENCE  TEACHING. 

state  his  ideas,  but  not  attempt  to  have  others  follow 
unless  they  choose  so  to  do. 

Now  let  the  teacher  add  any  desirable  names  which 
may  have  escaped  the  class. 

Third,  What  do  these  animals  need  in  order  to  live  ? 
Discuss  this  with  the  class  until  you  have  developed  the 
ideas  of — 

1.  Food  (including"  air  and  water). 

2.  Protection  (against  rain,  cold,  and  enemies). 
Should  either  of  these  (1  and  2)  fail,  what  must  the 

animal  do  ? 

Again  discuss  this  till  the  class  has  suggested 

1.  Must  seek  it  elsewhere  (migrate). 

2.  Prepare  beforehand. 

3.  Change  its  mode  of  life  (hibernate,  etc.). 
Illustrate  these  by  homely  examples.      The  first,  by 

children  gathering  berries  or  nuts  ;  sheep  in  a  bare  pas- 
ture ;  bee  on  a  clover  head,  etc.  The  second,  by  wood  and 
coal  stored  for  winter,  fruit  preserved,  hay  in  the  barn, 
etc.  The  third,  by  the  expedients  of  campers,  lost  per- 
sons, or  travelers,  etc.  Having  thus  presented  the  prob- 
lem and  got  it  before  the  class  in  a  clear  and  interesting 
way,  proceed  to  apply  it  to  the  various  animals  decided 
upon,  beginning  with  one  that  is  well  known. 

Fourth.  Let  us  now  see  how  the  animals  of  our  lists 
manage  when  winter  comes. 

Babbit. — What  does  it  eat  ?  (Herbage,  bark,  and 
grain.) 

How  is  it  protected  ?    (Warm  fur  and  burrow.) 

What  will  it  do  in  winter  ?  (Only  change  its  food  a 
little.) 

Raccoon.*— Eats  eggs,  crayfish,  insects,  fruits,  green 
corn,  birds,  etc. 

How  does  he  spend  the  winter  ?    Gets  very  fat  on  the 

*  Riverside  Nat.  Hist.,  vol.  v,  p.  357  ft. 


ANIMALS.  99 

abundant  food  of  summer  and  fall,  and  on  the  approach 
of  cold  weather  goes  into  a  hollow  tree  or  burrow  and 
hibernates  till  spring. 

Of  what  use  is  the  fat  to  him  ?  (Keeps  him  warm 
and  supplies  the  needs  of  the  body.) 

Skunk. — Eats  insects,  eggs,  young  birds,  mice,  frogs, 
etc. 

Can  this  food  be  had  in  the  winter  ?    (No.) 

How  does  the  skunk  manage  ?  (Much  as  the  coon, 
hibernating  in  holes,  where  numbers  huddle  together  for 
warmth.) 

Sq^uirrel. — Eats  nuts  and  acorns.  Gathers  stores  of 
these  and  hides  them  in  the  leaves,  hollow  trees,  and 
holes.  Is  warmly  clad  in  fur,  and  has  its  nest  in  hollow 
trees. 

How  will  he  spend  the  winter  ?  (Half-active  in 
holes.) 

Gray  Gopher. — Eats  grain,  young  birds,  mice,  etc. 
Burrows  along  in  the  ground  much  like  the  mole.  Hi- 
bernates in  stacks  and  dry  burrows. 

Striped  Gopher. — Eats  seeds,  mice,  young  birds,  etc. 
Unable  to  procure  these,  hibernates  in  dry  holes. 

Chipmunk. — Eats  nuts  and  grain,  which  are  carried 
to  its  burrow  in  its  cheek  pouches.  Lays  up  stores  for 
winter,  and,  closing  the  entrance  to  its  hole,  lives  through 
the  winter  in  a  half-hibernating  state. 

Muskrat — Lives  on  aquatic  vegetation  and  roots,  with 
sometimes  a  river  mussel,  which  it  carries  from  the  bot- 
tom of  the  water  to  some  log  or  stone  to  open.  Can 
such  food  be  found  in  the  winter  ?  (Yes.)  What  trouble 
will  the  rat  have  ?  (Ice  will  hinder  his  getting  at  it.) 
How  does  he  manage  ?  (Burrows  up  into  high  banks 
from  below  the  water  line,  or  in  ponds  with  flat  banks, 
cuts  down  the  rushes  and  water  plants  and  piles  them  up 
like  a  high  haycock,  and  then  burrows  up  into  these, 
forming  a  chamber  above  the  water  to  live  and  breathe 


100  SYSTEMATIC  SCIENCE  TEACHING. 

in.  Through  these  protected  passageways  it  can  always 
get  at  its  food.) 

Woodchuck.— Eats  herbage,  buds,  and  grain.  This 
food  can  not  be  had  in  the  winter,  and  the  animal  hiber- 
nates in  its  holes. 

Mole. — Lives  on  worms,  grubs,  etc.,  which  it  burrows 
after  through  the  loose  earth.  Can  these  be  found  in 
winter  ?  (Yes,  but  deeper,  and  the  mole  is  active  all  the 
year.) 

Mink. — Eats  frogs,  snakes,  crayfish,  snails,  fish,  rats, 
mice,  rabbits,  and  birds,  if  it  can  get  them.  This  food 
can  be  had  in  winter,  and  the  mink  remains  and  is 
active. 

Bat  (Red  or  Black). — Lives  on  insects  caught  on  the 
wing.  Are  insects  flying  about  in  the  winter  ?  (No.) 
Bats  cluster  in  caves  or  hollow  trees,  and  hibernate.  (See 
some  account  of  Mammoth  Cave  and  saltpeter  dirt.) 

Bobin. — Worms  and  fruit.  No  protection  or  food  in 
winter,  and  hence  must  go  (migrate)  to  localities  where 
food  is  found. 

Warbler. — Small  insects  eaten.    Migrates. 

Swallow. — Eats  small  insects  caught  on  the  wing.  As 
the  weather  becomes  cool  these  insects  hide  in  grass, 
under  banks,  etc.,  or  perish.  What  will  the  swallow 
do  ?    (Ply  to  warmer  climate.) 

Butcher  Bird. — Eats  insects,  small  birds,  mice,  etc. 
Migrates. 

English  Sparrow.— Seeds  and  insects.  Stays  and  is 
active. 

Snowbird. — Eats  seeds.  Warm  feathers.  Stays  and 
is  active. 

Cow  Blackbird.— Eats  insects.    Migrates. 

Meadow  Lark. — Eats  larvae  and  insects.    Migrates. 

Blue  Jay. — Eats  grubs  in  hazelnuts  and  acorns,  fruits, 
and  perhaps  grain.  Is  warmly  clothed  in  feathers,  and 
many  remain  all  winter  and  are  active. 


ANIMALS.  101 

Crow. — Feeds  on  gi-ain,  carrion,  and  almost  anj^thing 
edible.     Warmly  clad.     Many  remain  during  the  winter. 

Hummillg  Bird.— Nectar  and  small  insects  from  flow- 
ers.    Migrates. 

King^sher.— Small  fish.  Water  freezes,  and  so  must 
migrate. 

Woodpecker.— Grubs  from  dead  trees  and  fruits.  May 
remain  during  winter,  in  active  life. 

Owl.— Small  birds  and  animals.  May  remain,  pro- 
tected in  its  holes  in  trees. 

Hawk.— Small  birds  and  animals.  Not  well  protected 
against  cold,  and  food  scarce  ;  hence  mostly  migrate. 

CluaiL— Eats  grain.  Burrows  in  the  snow  under  grass 
or  bushes  for  protection,  and  remains  active. 

Prairie  Chicken. — Eats  grain,  and  seeks  protection  in 
thick  grass  or  in  snow  banks.     Remains  active. 

Snipe. — Eats  worms  found  in  the  mud.    Must  migrate. 

Goose. — Feeds  on  grain.    Migrates  to  find  open  water. 

Duck. — Feeds  on  grain,  water  plants,  and  animals. 
Migrates  to  open  water. 

Turtle. — Feeds  on  insects  and  water  animals.  Buries 
itself  in  the  mud  at  the  bottom  of  ponds  in  the  fall,  and 
remains  in  a  torpid  condition  till  early  spring. 

Snake. — Eats  insects,  frogs,  and  small  animals.  Hi- 
bernates in  holes  or  in  the  mud  of  ponds. 

Frog. — Eats  insects.  Buries  itself  in  the  mud  of 
ponds,  and  is  torpid  till  early  spring. 

Perch. — Eats  insects  and  other  fish.  Active  in  the 
water  under  the  ice. 

Honeybee. — Eats  nectar  of  fiowers.  Lays  up  store 
during  the  summer.  Through  the  winter  the  bees  clus- 
ter together  over  the  combs  in  the  hive,  thus  keeping 
themselves  and  the  honey  warm. 

Bumblebee. — Lives  on  the  nectar  of  flowers.  No  stores 
are  laid  up.  Most  of  the  bees  die,  but  a  few  queens  hiber- 
nate under  bark,  moss,  or  grass. 


102  SYSTEMATIC  SCIENCE  TEACHING. 

Hornets. — Catch  insects  for  food,  although  they  also 
feed  on  nectar  and  juice  of  fruits.  Their  paper  nests  are 
deserted  in  the  fall,  and  only  a  few  queens  survive  by 
hibernating-,  much  as  the  bumblebee. 

Ants. — Eat  almost  anything — sugar,  nectar  (if  they 
can  get  it),  dead  insects,  etc.  Pass  the  winter  in  their 
"  hills  "  in  a  torpid  condition. 

Butterfly. — Caterpillar  eats  leaves  and  the  insect  eats 
nectar.  Most  buttei flies  die,  but  the  caterpillars  enter  the 
pupa  state  in  the  fall,  and  so  remain  till  spring. 

Moth. — Caterpillars  eat  leaves  and  the  insect  eats  nec- 
tar. Most  die  after  laying  their  eggs,  but  the  caterpillars 
spin  cocoons  of  silk  in  w^hich  to  pass  the  winter  in  pupa 
state,  or  (as  hawk  moths)  burrow  into  the  ground  and 
enter  pupa  state. 

Fly. — Eats  liquid  food.  Hibernates  in  cracks  or  as 
pupas. 

Mosqnito. — Blood  of  animals.  The  pupa  passes  the 
v^inter  in  the  water  of  ponds. 

Plant  Beetle. — Lives  on  herbage.  Beetles  die  after  lay- 
ing eggs,  and  the  young  pass  the  winter  as  pupae  in  the 
ground. 

Sqnash  Bug. — Lives  on  the  juices  of  the  squash  vine. 
The  bugs  hibernate  under  rubbish  or  in  crevices. 

Aphis. — Feeds  on  the  juices  of  plants.  Most  perish  in 
the  fall,  the  eggs  surviving  to  produce  new  colonies  in 
the  spring.  (See  Comstock's  Insects,  pp.  158  and  637 ;  or 
Harris,  pp.  237-240.) 

Grasshopper.— Eats  herbage.  Perishes  when  food  is 
gone,  the  eggs  laid  in  the  ground  surviving. 

Libellula  (dragon  fly). — Lives  on  insects  caught  on  the 
wing.  The  larvae  and  pupae  pass  the  winter  as  active 
water  animals.     Some  may  migrate. 

Spider. — Lives  on  the  juices  of  insects.  Passes  the 
winter  by  hibernating  in  nests  of  web  made  in  cracks, 
etc.,  or  in  the  e^gg  state. 


ANIMALS.  103 

Crayfish. — Eats  decaying  or  live  fish,  etc.,  of  ponds 
and  streams.  Passes  the  winter  as  an  active  water  ani- 
mal. 

Land  SnaiL — Eats  herbage.  Closes  the  mouth  of  the 
shell  and  hibernates. 

Fond  SnaiL — Eats  herbage  of  aquatic  plants  in  the 
water,  and  is  active  below  the  ice. 

Clam. — Lives  on  small  animals  in  the  water,  and  in 
winter  goes  into  deeper  water. 

Earthworm. — Burrows  in  the  earth  and  lives  upon  the 
decaying  or  other  material  it  contains.  In  winter  (or 
dry  weather),  when  the  ground  becomes  hard,  worms 
descend  into  deep  burrows  and  hibernate  in  a  closely 
coiled  knot. 

Review. — None  advised.  Examine  the  notes  made  by 
the  pupils,  and  commend  the  neat  and  orderly  ones. 

Next  step  in  Animal  lessons  is  XXXII — Man  and 
his  Surroundings. 


STEP  XXX.— GRAVITATION  HOLDS  THE  SOLAR 
SYSTEM  TOGETHER. 

The  object  of  this  step  is  to  enlarge  the  pupil's  con- 
ception of  the  earth  and  planets,  to  take  up  certain 
points  in  physics,  gravitation,  etc.,  which  do  not  natur- 
ally fall  in  with  the  work  of  Step  XXXI. 

Time  needed. — About  twenty  lessons  of  twenty  min- 
utes each,  and  by  choice  in  the  early  winter,  and  either 
before  or  after  Step  XXXI — Molecules. 

MateriaL — The  most  needful — in  addition  to  the  globes, 
etc.,  of  the  previous  steps — will  be  a  large  magnet  and 
knitting  needle,  a  spring  balance,  and  glass  fish  globe. 

Preparation  of  the  Teacher.— Read  thoughtfully  the 
parts  of  Lockyer's  Elements  of  Astronomy  (American 
edition),  which  are  found  under  Chapter  XVI,  page  272, 
or  the  subject  of  gravitation  in  any  good  work  on  physics. 
Then  go  through  this  step  and  test  the  experiments,  etc., 
modifying  where  necessary. 

It  is  to  be  remembered  that  these  lessons  are  planned 
on  the  supposition  that  the  pupils  have  had  the  previous 
step  (XXIV). 

The  Lessons. 

The  connection  can  be  made  by  the  following  review 
questions : 

What  motions  has  our  earth  ?  (On  its  axis  and  about 
the  sun.) 

What  other  moving  bodies  have  we  studied  ?    (Plan- 
ets, comets,  and  moons.) 
104 


GRAVITATION  AND  THE  SOLAR  SYSTEM.       105 

How  is  the  motion  discovered  ?     (By  watching.) 

Which  way  do  all  the  planets  "  wander "  ?  (They 
seem  to  the  observer  to  "  wander  "  opposite  to  the  motion 
of  the  hands  of  a  watch,  but  with  some  retrograde  move- 
ments and  some  sidewise  deviations  from  a  straight 
course.  It  is  this  irregularity  that  procured  for  them 
the  name  of  "  wanderers.") 

Around  what  ?    (The  sun.) 

In  what  plane  f    (Nearly  that  of  the  ecliptic.) 

In  what  constellations  do  they  then  always  appear  ? 
(Zodiacal.) 

Are  their  orbits  interior,  or  exterior,  to  the  earth's  ? 
(Both.) 

Which  will  only  appear  as  morning  and  evening 
stars  ?     (Interior.) 

Which  will  have  phases  like  the  moon  ?  (Interior.) 
Why? 

Which  can  be  seen  at  midnight  ?    (Exterior.) 

Name  the  interior  planets. 

Name  the  exterior. 

How  many  large  planets  has  the  sun  in  his  "  family  "  ? 
(Eight.) 

How  large  is  the  earth  compared  with  the  sun  ?  (Il- 
lustrate as  follows.) 

If  the  sun  were  a  12-inch  globe,  what  would  repre- 
sent— 

Mercury  ?    (1  mm.  pin  head.) 

Venus  ?     (2^  mm.  pin  head.) 

Earth  ?     (3  mm.  pin  head.) 

Mars  ?    (2  mm.  pin  head.) 

Jupiter  ?     (30  mm.  ball.) 

Saturn  ?    (24  mm.  ball.) 

Uranus  ?     (11  mm.  marble.) 

Neptune  ?     (13  mm.  marble.) 

How  far  is  the  earth  from  the  sun  ?  (About  93,000,- 
000  miles.) 


106  SYSTEMATIC  SCIENCE  TEACHING. 

How  shall  we  place  our  pins  and  balls  to  show  the 
relative  distances  of  the  other  planets  ? 

Do  the  interior  planets  have  longer,  or  shorter,  years 
than  ours  ? 

How  about  the  "years  "  of  Neptune  ?  (One  hundred 
and  sixty-five  years  of  ours.) 

Why  is  it  best  for  us  to  have  short  days  and  nights  ? 
(Frequent  rest.) 

Why  to  our  advantage  to  have  short  and  frequently 
recurring  seasons  f  (Change,  and  we  learn  by  experi- 
ence how  to  meet  them.) 

Which  planets  have  moons  f  (All  the  exterior,  and 
the  earth.) 

How  many  moons  has  each  ?  (1,  2,  5, 8, 4, 1.  See  Step 
XXIV.) 

What  did  we  learn  from  Jupiter's  moons  ?  (Speed  of 
light.) 

What  strange  members  of  our  "  family "  do  we  at 
times  see  ?    (Comets.) 

Name  the  star  groups  through  which  the  sun  seems  to 
pass,  beginning  with  April.     (The  Ram,  the  Bull,  etc.) 

Inertia. — Let  us  think  of  a  few  common  things  before 
we  consider  the  next  subject. 

How  long  will  this  globe  (or  anything)  remain  quietly 
on  my  desk  ?     (Till  something  makes  it  move.) 

Can  anything  not  alive  set  itself  in  motion  ?     (No.) 

A  baseball  is  "pitched."  What  ways  are  there  of 
stopping  it  ?     (Bat,  caught,  or  strikes  something.) 

What  can  it  "  strike  "  ?     (Air,  ground,  etc.) 

Suppose  it  did  neither  of  these — had  nothing  to  strike  ? 
(Never  stop.) 

Be  quite  sure  of  these  things,  and  then  you  can  an- 
swer the  next  question. 

Have  dead  things,  like  stones,  balls,  or  even  planets 
any  control  over  their  own  motions  ?    (No.) 

If  at  rest  f    (Will  stay  so  till  made  to  move.) 


GRAVITATION  AND  THE  SOLAR  SYSTEM.       107 

If  they  are  in  motion  f  (Will  keep  going  till 
stopped.) 

Which  way  will  they  "  keep  going  "if  there  is  noth- 
ing to  hit  against  ?  (Straight  on  the  course  in  which 
they  started.)  This  inability  to  change  itself  is  called 
inertia. 

But  do  the  moons  and  planets  move  "  straight  on  "  ? 
(No,  in  circles,  or  ellipses.) 

Let  us  see  if  we  can  find  out  why  in  curves  and  not 
straight  on. 

If  I  throw  a  ball,  what  must  it  push  aside  to  go  on  ? 
(Air.) 

Will  this  stop  it  somewhat  ?    (Yes.) 

Will  it  go  quite  as  far  ?    (No.) 

If  I  throw  the  ball  up,  does  it  stop  after  a  time  ? 

Do  you  think  it  is  the  air  that  stops  it  so  quickly  ? 

Why  not  the  air  ?  (Does  not  go  as  far  as  if  thrown 
the  usual  way.) 

Gravitation. — Suppose  for  a  moment  it  was  only  the 
air,  what  would  happen  when  the  ball  came  to  rest  ? 
(Stay  there.) 

Yes,  for  the  ball  has  no  power  to  set  itself  going,  and 
certainly  the  air  which  stopped  it  would  not;  so  you 
would  have  to  get  a  ladder  or  pole  with  a  hook  to  pull 
down  the  ball  every  time  it  went  up  in  tennis  or  base- 
ball. 

But  we  are  not  forced  to  this  inconvenience,  for  what 
happens  ?    (The  ball  falls.) 

Is  it  alone  balls  that  fall  ?  {Everything  that  has  no 
support.) 

"  Everything "  is  a  very  broad  word,  and  includes  a 
great  many  things.  Let  us  name  a  number  of  examples 
and  see  if  we  need  to  say  "  most "  or  "  nearly  "  before  it. 
(No,  as  far  as  we  can  observe,  there  are  no  real  exceptions 
to  the  rule  that  everything  falls.) 

Which  ivay  do  things  fall  ?    (Down.) 


108  SYSTEMATIC  SCIENCE  TEACHING. 

Yes,  and  "  down  "  with  us  is  always  straight  toward 
the  center  of  the  earth.    How  about  the  Chinese  ? 

We  call  the  force  which  draws  all  thing^s  as  close  as 
possible  to  the  center  of  the  earth  gravitation.  I  will 
place  this  large  magnet  on  one  side  of  the  room  and 
hang  this  magnetized  knitting  needle  before  you  on  the 
other  side.  Now  it  is  still.  I  bring  the  magnet  slowly 
across  the  room  toward  it.  See !  Even  at  quite  a  distance 
the  needle  begins  to  move.  Can  you  see  anything  reach- 
ing out  from  the  magnet  to  the  needle  ?    (No.) 

The  nearer  I  bring  the  magnet  the  more  strongly  it 
seems  to  draw  the  needle. 

Just  as  wonderfully  and  as  unseen  does  the  earth  reach 
out  and  pull  everything  to  itself. 

How  does  the  nearness  of  the  magnet  affect  the  needle  ? 
(The  nearer,  the  more  powerful.) 

Cavendish's  experiment  is  interesting  and  helpful  here. 
He  took  two  huge  balls  of  lead  and  put  them  on  a  kind 
of  turntable  (see  Lockyer,  p.  284) ;  then  by  a  fine  wire  or 
thread  he  suspended  a  rod  ending  in  two  small  balls  of 
lead.  The  rod  was  of  such  length  as  to  bring  the  little 
balls  just  opposite  the  centers  of  the  larger. 

When  the  rod  was  perfectly  still,  the  large  balls  were 
carefully  brought  near  the  small  ones,  and  at  the  same 
time  careful  watch  was  made  to  see  if  the  large  balls 
pulled  (attracted)  the  small  ones  toward  them. 

This  was  tried  on  both  sides,  and  in  every  case  the 
small  balls  were  seen  to  move  a  little  toward  the  big 
ones. 

Does  lead  attract  lead  ?    (Yes.) 

A  balance  or  scale  for  weighing  things  is  used  to 
measure  this  pull  of  the  earth  on  various  things.  Do  you 
know  of  anything  which  has  no  weight  ? 

The  more  there  is  of  butter,  sugar,  shot,  etc. ?    (The 

more  it  iveighs.) 

Do  other  motions  interfere  with  this  pull  ? 


GRAVITATION  AND  THE  SOLAR  SYSTEM.       109 

Hang  a  weight  on  a  spring  balance  and  move  it  in 
difPerent  directions.    Does  it  still  weigh  the  same  ?    (Yes.) 

John,  how  much  do  you  weigh  ?  Would  you  weigh 
more,  or  less,  if  riding  along  on  a  bicycle  ?  On  a  fast 
train  ?  Going  up  in  an  elevator  ?  Coming  down  ?  (The 
same.) 

Could  you  play  ball  on  a  swiftly  moving  steamer  ? 
(Yes,  except  for  the  wind.) 

If  a  cannon  were  loaded,  what  would  keep  the  ball 
from  falling  ?    (Bottom  of  the  bore  of  the  cannon.) 

If  the  ball  were  loose  and  the  cannon's  mouth  slightly 
tipped  down  ?    (Roll  out.) 

What  would  it  begin  to  do  the  instant  it  was  out  of 
the  cannon  ?    (Fall.) 

Suppose  the  ball  back  again,  and,  instead  of  tipping 
the  cannon,  let  us  fire  the  ball  out.  Will  it  again  begin 
to  fall  the  instant  the  cannon  ceases  to  hold  it  up  ? 
(Yes.) 

While  it  is  falling  what  other  motion  will  it  have  ? 
(Straight  forward.) 

How  long  will  it  have  to  go  ahead  ?  (As  long  as  it 
takes  to  fall  to  the  ground.) 

How  many  ways  will  the  ball  be  moving  at  once  ? 
(Two.) 

Do  either  of  these  interfere  with  the  other  ?    (No.)  * 

Resultant  Motion.— All  have  been  downstairs.  What 
two  ways  did  you  go  at  once  ?    (Forward  and  down.) 

Yes,  you  might  have  walked  straight  along  the  upper 
floor  till  over  the  lowest  step,  and  then  taken  all  the 
down  at  once  by ?    (Jumping.) 

Who  has  rowed  across  a  river  ?  Well,  Samuel,  tell  us 
about  it. 

*  I  trust  the  class  will  be  bright  enough  to  raise  some  objec- 
tions here  at  this  difficult  point.  If  so,  a  most  helpful  review 
can  result. 


110  SYSTEMATIC  SCIENCE  TEACHING. 

"  I  had  to  row  a  little  wpstream  all  the  time,  as  the 
current  carried  me  down  so  fast." 

How  many  ways  did  you  then  move  at  once  ?     (Two.) 
Who  can  draw  a  diagram  on  the  board  to  illustrate 
these  two  things  (stairs  and  boat)  ? 

Now  watch  me  while  I  carry  this  ball  at  the  height  of 
ray  head  to  the  other  end  of  the  room  and  then  drop  it 
down  into  this  basket.  Who  can  suggest  an  easier  way  to 
get  the  ball  from  my  desk  to  the  basket  ?     (Throw.) 

Yes,  but  how  ?  What  motion  shall  I  give  the  ball  ? 
(Straight  ahead.) 

What  will  make  it  go  down  f  (Gravitation,  or  the 
attraction  of  the  earth.) 

Now  watch  while  I  try  !  (Throw  gently  at  first.)  Why 
did  it  fall  short  of  the  basket  ?  (You  did  not  throw  Jiard 
enough.) 

What  difference  did  that  make  ?  (It  did  not  have  time 
to  pass  over  the  horizontal  distance  before  it  reached  the 
floor.) 

What  must  I  do  ?    (Make  it  go  swifter.) 
Now  watch  it !    What  was  the  path  it  followed  ?    (A 
curve.)    Who  can  draw  a  diagram  of  this  ? 

Continued,  what  would  a  "curve"  become  ?  (Circle 
or  ellipse  or  parabola,  etc.)     Explain  the  difference. 

I  want  you  to  watch  the  flight  of  balls  and  such  things 
and  see  if  they  always  take  this  curved  path.  A  boy  puts 
a  stone  in  a  sling  and  whirls  it  rapidly  around ;  while 

in  the  sling  tlie  stone  travels  in  a ?    (Circle.) 

Does  it  pull  on  the  string  ?  (Yes.)  Showing  that  it 
wants  to  go  straight  forward. 

The  moment  the  sling  is  loosed  the  stone ?    (Flies 

off.) 

A  carriage  wheel  revolves  rapidly.  As  it  goes  through 
the  mud  some  sticks  to  the  wheel,  but  the  rapid  motion 
makes  it  fly  off  and  "spatter."  Why?  (The  mud  is 
more  and  more  inclined  to  leave  the  wheel  and  go  in  a 


GRAVITATION  AND  THE  SOLAR  SYSTEM.       m 

straight  course — inertia — till  at  last  this  tendency  to  keep 
straight  on  is  stronger  than  the  adhesive  power  of  the 
mud,  and  off  it  goes.) 

Huge  grindstones,  used  to  polish  steel  things,  and 
driven  at  a  high  speed,  are  apt  to  burst  and  injure  the 
men  working  about  them.  Why  do  they  burst  ?  (There 
is  a  force  which  holds  the  stone  together,  but  the  rapid 
whirling  motion  causes  the  outer  portions  to  pull  in 
their  effort  to  move  straight  ahead,  till  at  last  pieces  do 
fly  off  if  the  motion  be  swift  enough.) 

Put  a  cupful  of  colored  water  in  a  round  fish  globe ; 
tie  a  cord  about  the  neck  and  suspend  by  a  long  string 
from  the  ceiling ;  whirl  the  globe  around  in  the  direc- 
tion of  the  hands  of  a  watch  till  the  string  is  well  twisted, 
and  then  give  it  one  whirl  in  the  opposite  direction. 
The  twisted  string  will  keep  up  the  motion,  and  the  water 
rise  into  a  ring  around  the  largest  part  of  the  globe.* 
Why  does  it  rise  into  this  ring  ?     (Inertia.) 

If  elastic  hoops,  a  ball  of  soft  clay,  or  a  drop  of  melted 
metal  or  rock  could  be  rotated  in  the  same  way,  what 
would  happen  ?  {Bulge  at  the  middle  and  flatten  above 
and  below.) 

Scientists  have  found  that  our  earth  is  twenty-six 
miles  smaller  from  pole  to  pole  (show  on  a  globe)  than 
through  the  equator. 

How  do  you  suppose  that  happened  ?  (Daily  revolu- 
tion.) 

But  if  we  are  spinning  around  at  such  a  rate  why  does 
the  earth  not  fly  to  pieces  ?  (Is  not  spinning  fast  enough 
to  overcome  gravitation.) 

Why  dio  people  not  fly  off?  (Gravitation  holds  them  on.) 

What  else  is  held  on  by  the  attraction  of  the  earth  ? 
(Name  a  number  of  things.) 


*  A  rotator  or  whirling  table  will,  of  course,  be  better  if  oiio 
is  to  be  had. 


112  SYSTEMATIC  SCIENCE  TEACHING. 

What  causes  the  barometer  *  to  rise  and  fall  ? 
(Weight  of  the  air  varies.)  Then  the  air  has  weight; 
and  weight  is  the  measure  of  what  force  ?    (Gravitation.) 

Does  the  attraction  of  the  earth  extend  to  the  air  ? 
How  high  ?  (To  the  top.)  That  there  really  is  an  upper 
surface  to  this  ocean  of  air  that  we  live  at  the  bot- 
tom of,  is  shown  in  various  ways.  One  is,  that  "  falling 
Stars"  (see  Lockyer,  chap,  xi)  only  become  visible  at  a 
certain  distance  above  the  earth.  The  space  through 
which  the  earth  is  moving  seems  to  have  a  great  num- 
ber of  fragments  of  cold  stone  or  metal,  which  are 
swiftly  moving,  like  the  earth  and  moon,  about  some 
center.  As  the  earth  travels  on  in  her  journey  around 
the  sun  many  of  these  come  so  near  that  they  are  at- 
tracted to  the  earth,  and  fall  so  swiftly  through  the  air 
as  to  take  fire—burn  up.  What  makes  them  come  to 
the  earth  ?     (Gravitation.) 

Then  the  earth  not  only  attracts  rocks  and  people  and 
air,  but  bodies  beyond  the  air. 

Who  can  now  tell  why  the  moon  goes  in  a  circular 
orbit  about  the  earth  ?    {EartKs  attraction.) 

Yes,  we  feel  quite  sure  that  is  what  keeps  her  from 
flying  off.  But  the  attraction  alone  would  make  her  do 
what  ?    (Fall  to  the  earth.) 

What  made  the  ball,  etc.,  move  in  a  curved  line  ?  (A 
double  motion — onward  and  down  at  once.) 

So,  what  other  motion  must  the  moon  have  ?  (On- 
ward.) 

Illustrate  on  the  board  this  continual  falling,  but, 
while  falling,  having  an  onward  motion,  by  which  it 
never  gets  out  of  its  curved  orbit.  Always  trying  to  fly 
off,  like  the  stone  in  the  sling,  it  is  restrained  by  the 
attraction  of  the  huge  earth,  and  so  travels  about  her — 
once  in  how  often  ?     (About  a  month.) 

*  See  Step  XV. 


GRAVITATION  AND  THE  SOLAR  SYSTEM.     113 

Can  it  be  that  this  powerful  force  reaches  out  to  the 
sun? 

We  might  reply,  Why  not  ?  We  agreed  that  every- 
thing attracted  everything  else,  and  the  great  sun  must 
not  be  left  out. 

Were,  then,  the  ancients  right  in  saying  the  sun  re- 
volved around  the  earth  ?  (No,  for  we  know  the  reverse 
is  true.) 

Why  must  this  be  ?  (The  sun  is  so  very  much 
larger.) 

Imagine  for  a  moment  that  a  boy  had  a  stone  weigh- 
ing a  ton  in  his  sling :  which  would  be  forced  to  go 
around  the  other  ?    (The  boy.) 

Yes,  and  so  the  sun  holds  the  earth  in  her  orbit,  as  the 
earth  holds  the  moon. 

How  many  motions  must  the  earth  have  to  do  this  ? 
(Two  :  a  falling  and  also  an  onward  motion.) 

Class  now  copy  Fig.  41,  p.  93,  of  Lockyer,  and  with 
these  in  hand  further  discuss  this  :  how  that,  at  every 
point  in  its  orbit,  the  inertia  of  the  earth  impels  in  a 
straight  line,  which  the  continual  pull  of  the  sun  changes 
into  a  curve. 

Tides. — That  the  sun  attracts  the  earth  is  plain.  Does 
the  moon  also  attract  the  earth  ?  (Yes,  for  the  earth  is 
only  another  of  the  "  everythings.")  But  we  have  very 
plain  evidence  of  this  pull  in  certain  things  which  can 
be  seen  every  day  on  the  seashore.  Twice  a  day  the 
water  about  the  wharves  and  along  the  shore  rises  for 
six  hours  and  then  falls  for  six.  This  rise  and  fall  is 
called  the  tide,  from  a  word  which  refers  to  its  regular 
occurrences.  What  are  two  ways  in  which  land  can  be 
flooded  with  w^ater  ?  (A  rise  of  the  water  or  sinking 
of  the  land.) 

It  was  long  ago  noticed  that  as  the  moon  rose  in  the 
sky  the  tide  rose,  and  soon  after  she  began  to  descend  in 
the  west  the  tide  began  to  fall. 
9 


114  SYSTEMATIC  SCIENCE  TEACHING. 

Why  was  this  ?    (The  moon  raised  the  water.) 

When  I  brought  the  magnet  across  the  room  toward 
the  magnetized  needle  how  did  distance  seem  to  affect 
the  result  ?  (The  less  the  distance  the  stronger  the  at- 
traction.) 

Now  the  earth  revolves  on  its  axis  once  in ? 

(Twenty-four  hours.) 

The    moon    goes   around  the    earth    once    in ? 

(About  thirty  days.) 

(Illustrate  this  with  the  large  and  small  globes.) 

So  the  east  coast  of  America  (see  map)  is  constantly 
coming  toivard  and  passing  by  the  moon.  The  Atlantic 
Ocean  lies  directly  under  the  moon  some  hours  before 
this  east  coast  does,  and  the  moon,  by  its  attraction  on 
the  near  water,  raises  a  wide  ridge  of  water.  As  the  land 
comes  under  the  influence  of  the  moon  it  is  too  stiff  to 
rise,  and  so  slides  right  into  the  ridge  of  water,  which 
rushes  up  on  to  the  land  and  makes  the  "  rising  tide  "  for 
six  hours. 

As  the  moon  is  left  behind,  her  influence  on  the  water 
becomes  less  and  less,  and  the  "  tide  falls  "  for  six  hours. 

Class  now  copy  on  chart  the  illustration  of  the  tides 
in  Burritt,  p.  284  (lower  cut),  or  some  other  which 
shows  the  earth,  sun,  and  moon  at  "spring  "  and  "neap " 
tides. 

With  these  in  hand  and  a  large  copy  on  the  board, 
an  ordinary  class  will  soon  remark  the  high  tides  on 
both  sides  of  the  earth  at  the  same  time,  and  will  learn 
that  the  swing  of  the  earth  about  an  axis  a  little  nearer 
the  moon  than  the  true  axis  causes  a  tidal  wave  opposite 
the  moon,  just  as  the  water  on  a  grindstone  that  is  hung 
on  an  axis  a  little  to  one  side  of  its  true  center  tends  to 
fly  off  most  at  the  point  farthest  from  the  axis. 

They  will  also  learn  how  to  explain  the  cause  of  the 
varying  height  (spring  and  neap)  of  the  tides,  due  to  the 
combined  or  opposed  attraction  of  both  sun  and  moon. 


GRAVITATION  AND  THE  SOLAR  SYSTEM.     115 

This  will  end  the  work  of  this  step,  except  the 

Constellations. — Choose  those  connected  with  the  story 
of  the  Golden  Fleece  (Bulfinch,  p.  158,  etc.,  Greek  Heroes, 
p.  107,  or  Tanglewood  Tales,  p.  180).  The  work  as  ar- 
ranged will  bring"  this  step  the  last  of  October  or  first 
of  November,  when  Aries— already  found  in  the  zodiac 
— can  be  seen.  The  myths  connected  with  this  ram 
were  given  in  the  previous  step  (XXIV). 

Gemini  were  also  found  and  spoken  of  at  that  time. 
Find  again  in  January  or  February. 

Lyra,  the  harp  on  which  Orpheus  played  with  such 
skill  as  to  cause  the  ship  to  move  oil*  the  beach  with  all 
her  crew  on  board,  can  be  found  in  the  south  and  south- 
west during  September  and  October,  or  again  in  April  or 
May  in  the  northeast  (see  Burritt,  p.  112,  and  Bul- 
liiich,  p.  227).    Its  chief  beauty  is  in  the  brilliant  star  Vega, 

Cygnus— the  Swan — lies  in  the  Milky  Way,  just  east 
of  Lyra,  and  can  be  seen  above  the  Harp  in  the  fall  or 
following  it  in  the  spring  and  summer.  It  is  easily 
found  by  the  two  lines  of  bright  stars  (in  the  body  and 
wings)  forming  a  cross.  One  myth  tells  us  that  after  his 
death  Orpheus  was  placed  as  this  constellation — next  his 
harp.  From  these  constellations  pass  to  a  review  of 
Draco,  Ursa  Major,  etc. 

The  age  of  pupils  taking  this  step  will  be  from  eleven 
to  thirteen,  and  it  will  not  be  impossible  for  the  teacher 
to  gather  them  at  some  elevated  place,  where  trees  or 
buildings  do  not  interfere  with  the  view  of  the  sky,  for 
an  occasional  observation  lesson. 

Choose,  if  possible,  some  platform  or  roof  where  the 
dew  and  dampness  of  the  grouud  will  not  endanger 
health,  and  have  several  dark  lanterns  or  other  shaded 
lights  at  which  they  can  consult  maps  of  the  stars  and 
other  aids.     If  cool,  some  place  to  warm  at  is  a  help. 

Railway  stations,  where  there  is  but  little  travel,  often 
meet  all  these  conditions  well. 


116  SYSTEMATIC  SCIENCE  TEACHING. 

In  any  case  continue  the  making  of  diagrams  of  the 
constellations,  and  add  them  to  the  portfolio  before  sug- 
gested (Step  VII). 

Clarke's  astronomical  lantern  is  a  useful  piece  of  ap- 
paratus, which  I  think  the  manufacturers  (D.  C.  Heath  <& 
Co.,  Boston,  Mass.)  would  not  object  to  having  bright  pu- 
pils copy.  It  consists  of  a  tin  box  with  a  ventilator  on 
top,  and  places  for  two  candles  (or  small  lamp)  inside. 
A  groove  above  and  below  the  open  front  holds  a  sheet 
of  glass  to  x^rotect  the  light  when  changing  the  cards. 
These  cards  are  the  same  size  as  the  glass,  blue  ground 
with  white  stars,  and  slide  in  the  grooves  outside  the 
glass. 

Bailey's  star  lantern  is  a  very  useful  thing.  The  next 
step  in  this  work  is  XXXV. 


STEP  XXXI.— THE  STUDY  OF  MOLECULES. 

An  outline  of  experiments  to  show  another  way  sharp  stones 
might  be  made.    See  Step  XX. 

Object  of  these  Lessons.— Primarily,  to  clear  the  way 
for  future  work  along  all  lines,  as  experience  has  proved 
the  great  value  of  clear  and  correct  ideas  regarding  the 
molecule  and  molecular  structure.  Whatever  future  sci- 
ence may  disclose,  the  molecular  theory  has  proved  a 
powerful  aid  in  all  physical  teaching ;  so  efficient  that  I 
never  should  attempt  to  give  ideas  of  heat,  light,  sound, 
etc.,  without  j/?rs^  studying  "the  molecule."  To  those 
who  may  urge  its  unfitness  for  eleven-year-old  pupils,  I 
can  confidently  point  to  more  than  one  class  of  nine-to- 
ten-year-old  children  who  have  in  after-work  plainly 
shown  the  results  in  clear  and  accurate  grasp  of  prob- 
lems involving  such  explanations. 

2.  This  work  is  a  broadening  of  the  child's  horizon  in 
physics,  and  an  introduction  to  exact  experiments  and 
note  keeping.  While  much  has  been  brought  to  notice 
in  minerals,  pebbles,  sharp  stones,  etc.,  it  was  only  for 
notice,  and  now,  with  added  experience  and  brain  power, 
we  invite  the  pupil  to  look  closer. 

3.  To  acquaint  the  child  more  fully  with  the  admi- 
rable "  metric  "  system  of  weights  and  measures,  that  the 
day  may  be  hastened  when  it  may  replace  our  present 
antiquated  and  cumbersome  system.  For  previous  work 
on  metric  measure  and  volume,  see  Steps  XXI  and 
XXVI. 

117 


118  SYSTEMATIC  SCIENCE  TEACHING. 


Material  Needed. 

The  advanced  nature  of  the  work  will  require  a  cor- 
responding outlay  in  time  and  money. 

Tables  should  replace  the  school  desk,  as  alcohol  and 
acid  would  mar,  and  the  slanting  surface  prevent  many 
experiments ;  but  be  very  economical  in  these,  as  a  few 
pine  boards  twelve  inches  wide  will  angwer  well.  Place 
these  rough  tables  (breast  high  for  the  standing  pupil)  in 
some  spare  room,  if  possible,  where  things  can  be  left 
without  the  breakage  and  loss  of  time  due  to  daily  get- 
ting out  and  storing  away.  Should  no  such  room  offer, 
two-feet  (wide)  tables  might  be  stood  on  edge  or  hinged 
against  the  wall  of  the  room  when  not  in  use,  and  could 
be  quickly  lifted  on  top  of  the  desks.  Each  pupil  should 
have  three  feet  in  length  of  space,  or  live  feet  for  two 
pupils. 

Some  place  to  store  the  apparatus  will  be  needed,  espe- 
cially where  it  has  to  be  gathered  up  at  the  close  of  each 
lesson. 

In  this  case  have  wooden  trays  or  boxes  for  each  thing 
(or  for  each  pupil). 

Water  will  be  needed  in  plenty,  and  jars  to  hold  the 
waste. 

Quantity  and  Cost— (For  a  class  of  thirty  to  work  in 
pairs.) 

15  50  c.  c.  graduated  cylinders  (glass). 

15  droppers  (rubber  bulb).  Make  the  opening  small 
in  a  flame. 

30  8-ounce  wide-mouthed  bottles  of  clear  glass  ("  mor- 
phine "  good). 

30  3-ounce  wide-mouthed  bottles  with  good  corks. 

15  feet  rubber  tubing  ^^  of  an  inch  in  diameter. 

30  vials  and  corks,  and  1  pound  of  No.  10  or  '*  dust " 
shot  to  fill  them. 


THE  STUDY  OF  MOLECULES.  119 

Half  a  pound  of  hydrochloric  acid. 

1  quart  alcohol. 

15  4-ounce  flat-bottomed,  wide-mouthed,  and  strong 
glass  flasks. 

15  rubber  corks  (1  perforation)  to  fit  flasks. 

2  pounds  thick  glass  tubing  (small  bore)  to  fit  rubber 
corks. 

1  triangular  file  to  cut  glass  tubing. 

2  pounds  bullets  or  buckshot  (largest  to  be  had). 
Quarter  of  an  ounce  iodine  in  bottle. 

2  pounds  eightpenny  wire  nails. 

30  small  bar  magnets.     (See  Step  III). 

Expansion  apparatus.    (Rod  and  indexing  needle.) 

Expansion  ball  and  ring. 

15  3-ounce  alcohol  lamps  (glass). 

1  pulse-glass. 

6  pudding  dishes,  flat-bottomed  and  10  cm.  deep. 

15  "  return  balls  "  (ball  on  piece  of  rubber  cord). 

8  dozen  glass  marbles,  uniform  size. 

30  slate  pencils.  30  skewers  from  butcher.  30  pieces 
copper  rod  (or  wire  nails  will  do).  All  these  nearly  the 
same  length  and  size. 

30  5  X  8  inch  notebooks,  opening  at  the  end  and  hav- 
ing wide  ruling.  Paper  tough,  and  not  too  highly  glazed 
(for  pencils).  It  is  better  for  the  teacher  to  get  these,  as 
it  saves  one  half  to  one  third  the  expense,  and  secures  a 
very  helpful  uniformity  in  size  and  quality. 

The  above  is  a  good,  serviceable  outfit,  and  the  most 
economical,  as  the  teacher^ s  time  is  too  valuable  to  be 
spent  in  devising  apparatus  when  it  can  be  so  cheaply 
bought. 

The  original  outlay  will  be  about  one  dollar  per  pupil, 
and  will  last  for  years. 

The  actual  expense  per  lesson  is  about  one  cent  for 
eight  pupils,  and  after  a  trial  no  one  will  ever  again 
hesitate  on  account  of  cost. 


120  SYSTEMATIC  SCIENCE  TEACHING. 

Breakage  can  hardly  be  avoided,  but  has  been  less- 
ened by  placing  twenty-five  cents  to  the  credit  of  each 
pupil — to  be  his  if  he  breaks  nothing ;  otherwise  applied 
oh  payment  of  damage.  Post  a  cost  list  of  all  apparatus, 
both  to  aid  pupils  wishing  to  experiment  at  home  and 
for  settlement  of  damages. 

Preparation  of  Teacher.— Tables  having  been  prepared 
and  apparatus  got  and  put  in  order,  go  through  the  fol- 
lowing lessons,  step  by  step,  till  the  subject  is  mastered 
and  apparatus  proved. 

Should  you  be  new  at  such  work,  find,  if  possible, 
some  more  experienced  friend  to  advise  and  assist ;  but 
do  the  experimenting  personally.  Two  or  three  briglit, 
reliable  pupils  can  assist — or,  better,  go  through  the  ex- 
periments at  the  same  time — and  will  afterward  be  able 
to  render  efficient  aid  in  handling  a  large  class. 

Cards. — By  the  aid  of  hectograph  or  printer  prepare 
fifteen  cards  of  each  experiment  like  those  in  the  follow- 
ing "  experiments."  Otherwise  the  experiments  must  be 
placed  on  the  blackboard  and  copied. 

Time. — About  twenty-five  or  thirty  lessons  of  thirty 
minutes  each,  at  such  time  of  the  day  as  the  schoolroom 
will  permit.  This,  in  places  where  there  is  no  special 
room,  had  best  be  after  school  hours.  Dismiss  the  rest  of 
the  school,  and  turn  the  room  into  a  laboratory. 

I  Outline  of  Work. 

1.  What  is  a  molecule  ? 

2.  How  large  f    Ex.  1. 

3.  What  is  a  possible  shape  f    Ex.  2. 

4.  Are  there  spaces  between  them  ?    Exs.  3  and  4. 

5.  Can  molecules  be  forced  nearer  together  ?    Ex.  5. 

6.  What  holds  them  together  in  solids,  etc.  ? 

Cohesion,  Ex.  6 ;   adhesion,   Ex.  7 ;  gravitation, 
Ex.8. 


THE  STUDY  OP   MOLECULES.  121 

7.  Effects  of  varying  strength  of  these  forces. 

Solids,  Ex.  9  ;  liquids,  Ex.  10 ;  gas,  Ex.  11. 

8.  Are  the  molecules  of  these  still,  or  in  motion  f 

Ways  they  may  move.     Ex.  12. 
Work  needed  to  change  their  state. 
For  work  we  can  get : 

1.  Change  of  place.     Ex.  13. 

2.  Change  of  shape.     Ex.  14. 

3.  Sound.     Ex.  15. 

4.  Light.     Ex.  16. 

5.  Magnetism.     Ex.  17. 

6.  Electricity.     Ex.  18. 

7.  Heat.     Ex.  19. 

9.  If  work  does  one  thing,  it  can  not  at  the  same  time 
do  as  much  of  something  else. 

10.  The  effects  of  heat  vibration. 

Expands  solids,  Ex.  20  ;  liquids,  gas,  and  vapor. 

Ex.  21. 
Sets  in  motion  (convection)  liquids,  gases,  and 

vapors.     Ex.  22. 
Melts  solids,  vaporizes  liquids,  and  decomposes 

gases.     Ex.  23. 

11.  How  are  the  heat  vibrations  transmitted  f    (Con- 
duction.)    Ex.  24. 

12.  Do  all    substances    transmit    vibrations  equally 
well  f    Ex.  25. 

13.  Is  much  force  exerted  by  expansion  and  contrac- 
tion ? 

14.  What  is  the  effect  of  sudden  expansion  or  con- 
traction ? 

15.  How  might  rocks  have  been  cracked  into  sharp 
fragments  ?    (Continues  Step  XX.) 


122       '    SYSTEMATIC  SCIENCE  TEACHING. 


The  Lessons. 

I  trust  your  pupils  have  been  permitted  to  be  your 
confidential  assistants  in  all  the  preparation  of  ordei*s  for 
apparatus,  unpacking,  washing,  and  putting  away.  If 
this  has  been  the  case,  they  are  now  anxiously  waiting, 
and  no  time  should  be  lost. 

Lesson  1.— What  is  a  molecule? 

In  order  to  explain  what  we  see  about  us,  scientists 
have  been  obliged  to  suppose  all  things  we  see  made  up 
of  tiny  parts  called  molecules.  Glass,  iron,  water,  and 
air  are,  one  and  all,  composed  of  the  molecules  about 
which  we  are  now  to  study  ;  and  a  molecule  is  the  small- 
est particle  of  anything  which  retains  its  identity  (is 
itself). 

You  may  do  what  you  please  to  salt — crush,  pound, 
heat,  cool,  or  dissolve  it — but  just  as  long  as  the  tiniest 
particle  of  it  remains  true  to  name  it  is  still  salt;  the 
smallest  conceivable  particle  will  be  a  molecule  of  salt. 
But  if  I  in  any  way  change  it  so  that  a  quantity  is  no 
longer  white,  salt  to  the  taste,  nor  will  crystallize  in  cubes, 
I  have  destroyed  the  molecules  of  salt,  and  they  become 
molecules  of  something  else,  or  split  into  still  smaller 
pieces  called  atoms. 

Talk  of  sugar  and  other  substances  till  this  is  clear. 
Have  some  of  the  chief  points  briefly  but  neatly  re- 
corded in  the  pupils'  notebooks,  reserving  at  least  a 
full  page  for  each  experiment,  so  as  not  to  crowd  the 
notes. 

Lesson  2. — Assign  tables.  Arrange  class  in  pairSy 
with  instructions  that  the  pupils  are  to  take  turns  in 
conducting  the  experiments.  (If  one  is  found  doing 
all  the  work,  the  case  calls  for  remedy.)  Give  each 
pair  a  card  like  the  following,  and  the  apparatus 
needed. 


THE  STUDY  OF  MOLECULES.  123 

Experiment  1.— How  large  is  a  molecule? 

Keep  notes. 

Measure  195  c.  c.  of  water  into  one  of  two  bot- 
tles, and  fill  the  other  with  the  same  water.  Do 
they  look  alike  ? 

Into  the  water  of  one  turn  5  c.  c.  of  ammo- 
nia, add  1  drop  of  copper-sulphate  solution,  and 
shake  or  stir.  By  comparison  with  the  other  bot- 
tle of  water  (look  through  and  also  down  into 
the  water),  can  you  see  that  the  200  c.  c.  are  col- 
ored ?  Now  count  while  you  drop  water  with  a 
dropper  into  the  empty  g^raduate  till  it  stands  at 
the  5  c.  c.  mark,  and  calculate  into  how  many 
parts  1  drop  of  copper  sulphate  has  been  divided 
to  color  200  c.  c.  of  water. 

After  a  reasonable  time  call  the  class  to  order  and  dis- 
cuss results.  These  will  vary  somewhat,  and  the  errors 
will  introduce  some  needed  instruction, 

1.  The  graduates  were  held  slanting,  and  some  read 
the  top  and  others  the  bottom  of  the  curved  upper  sur- 
face of  the  water,  etc. 

Graduates  in  hand,  show  the  class  that  accurate  meas- 
ure can  only  be  had  by  placing  the  graduate  on  a  level 
surface  (mark  the  place  with  a  pencil,  and  always  stand 
it  in  its  circle  to  read).  Place  the  eye  on  the  level  of  the 
surface  and  read  the  middle  of  the  curve. 

2.  Errors  in  counting  occurred.  Show  how  unreli- 
able one  trial  is,  and  get  them  to  suggest  ways  of  pre- 
venting error.  (Recount  and  average  results,  if  nearly 
alike,  or  make  a  third  count  and  reject  the  one  most  out 
of  the  way.  Let  another  boy  try  it  with  the  same  drop- 
per ;  drop  10  c.  c.  and  divide  by  2,  etc.) 

3.  The  200  c.  c.  of  water  was  not  seen  to  be  colored  by 
some.  Question  as  to  what  they  did,  and  bring  out  the 
need  of  exactly  following  instructions  and  the  use  of  a 


124  SYSTEMATIC  SCIENCE  TEACHING. 

standard  for  comparison  (bottle  of  water  like  the  195  c.  c, 
into  which  nothing  was  put). 

4.  Some  did  not  know  how  to  calculate  the  result. 
Let  the  teacher  here  write  a  model  set  of  notes  on  the 
board  and  work  it  out  with  the  class  as  follows : 

Experiment  1.  .Question. — How  large  is  a  mole- 
cule ? 

Apparatus,  50  c.  c.  graduate,  two  clean  bottles,  clear 
water,  and  dropper. 

1.  Put  50  +  50  +  50  +  45  c.  c.  water  in  bottle  =  195  c.  c. 

2.  Filled  the  second  bottle  with  same  water. 

3.  They  looked  alike. 

4.  195  c.  c.  water  -}-  5  c.  c.  ammonia  =  odor  and  200  c.  c. 

5.  (4)  +  1  drop  copper  -  sulphate  solution  =  bluish- 
white  flakes. 

6.  Shook  (5)  and  flakes  disappeared. 

7.  Compared  (6)  with  (2)  and  noticed  a  bluish  tinge. 

8.  Emptied  graduate  and  counted  drops  in  5  c.  c.  water 
=  96  drops. 

9.  Tried  (8)  again  =  105  drops. 

10.  Tried  (8)  again  =  97  drops  (reject  (9)). 

11.  Thomas  tried  (8)  =  95  drops. 

(96) 

12.  Average  drops  in  5  c.  c.  from  (8),  (10),  and  (11)  -J  97  > 

288      „,,  M 

=  -^  =  96  drops, 
o 

13.  200  c.  c.  -^  5  =  40.     40  X  96  =  3,840  drops  in  200  c.  c. 

14.  Conclusion :  1  drop  copper-sulphate  solution  was 
divided  into  3,840  parts.     Rather  small ! 

This  may  seem  tedious  work,  but  the  class  has  been 
well  occupied  and  no  time  really  lost. 

Endeavor  to  complete  this  in  one  lesson  (while  fresh 
in  mind),  for  the  inspiration  which  comes  from  •' some- 
thing attempted,  something  done  "  each  day. 

Lesson  3.— Spend  two  minntes  in  a  brisk  review  on 
yesterday's  work.     Then  on  the  board  average  the  results 


THE  STUDY  OF  MOLECULES.  125 

of  the  whole  class  as  to  drops  in  200  c.  c.  water.  (My 
result  has  been  about  4,600.) 

Tell  the  class  that  the  drop  of  copper  sulphate  solu- 
tion was  only  about  ^  copper-sulphate,  and  the  rest  was 
?    (Water.) 

Write  the  chemical  symbol  (CuSO*)  on  the  board. 
This  stands  for  the  least  possible  bit  of  copper  sulphate. 
What  do  we  call  it  ?  "A  molecule^  But  in  chemistry 
"  Cu  "  stands  for  an  atom  of  copper,  "  S  "  for  an  atom  of 
sulphur,  and  "  O4  "  for  4  atoms  of  oxygen. 

How  many  atoms  in  a  molecule  of  CuS04  ?     (Six.) 

Here  show  pieces  of  copper  and  sulphur  about  the 
same  in  size. 

Pass  them  about,  and  tell  me  which  is  heaviest  f 
(Copper.) 

Air  is  about  like  oxygen.  How  does  that  compare 
with  the  others  ?     (Lighter.) 

Scientists  have  weighed  these  carefully,  and  find  an 
atom  of  O  to  weigh  16,  S  to  weigh  32,  and  Cu  to  weigh 
63.4  times  as  much  as  an  atom  of  the  gas  (hydrogen)  they 
have  selected  as  the  standard  of  weight  for  atoms. 

Calling  63.4  an  even  64,  and  writing  the  symbol 
thus, 

Cu       S  O4 

64    32    16  X  4  =  64, 

we  see  that  the  ^  copper  sulphate  in  our  drop  of  solution 
was  only  y\  copper  by  weight,  and  so  our  division  of  real 
copper  becomes  200  c.  c.  x  23  (drops  in  one  c.  c.)  x  8  x  2^ 
=  4.600  X  20  =  92,000  parts,  the  copper  in  each  drop  of 
solution  was  divided  into  more  than  the  seconds  in  a 
whole  day !  And  each  of  these  92,000  parts  was  doubt- 
less made  of  many  atoms  of  copper ! 

A  wise  Englishman  (Sir  William  Thompson)  has 
studied  this  matter,  and  gives  this  illustration  : 

"  If  a  drop  of  water  were  magnified  till  as  large  as  the 


126  SYSTEMATIC  SCIENCE  TEACHING. 

earth,  the  molecule  would  then  probably  be  larger  than 
shot,  but  not  as  large  as  cricket  balls  "  (or  apples). 

Try  and  conceive  the  number  of  balls  or  apples  needed 
to  fill  this  great  earth  if  it  were  a  hollow  sphere. 

So  much  for  size. 

Experiment  2.— What  is  a  possible  shape  of  a  mole- 
cule ? 

Examine  a  vial  of  fine  shot  and  write  your  conclu- 
sions. 

State  clearly  to  the  class  that  we  know  nothing  of  the 
shape ;  but  have  the  pupils  name  other  shapes,  and  see 
the  difficulties  in  supposing  them  to  be  other  than  spher. 
ical. 

Lesson  4.— Are  there  spaces  between  the  molecules  of 
water  ? 

Experiment  3.— To  75  c.  c  of  water  add  25  c.  c.  of 
water  (measured  separately),  and  record  its  volume  thus  : 
75  +  25  =  (  ).  Now,  to  75  c.  c.  water  add  25  c.  c.  of  alco- 
hol; shake,  and  record  as  above.  To  75  c.  c.  of  water  add 
10  c.  c.  of  salt,  and,  when  dissolved,  record  volume. 

Note. — The  weak  alcohol  made  is  worth  saving,  but 
throw  the  salt  solution  away.  For  measuring  the  salt 
select  a  small  tin  box  that  will  hold  about  10  c.  c. ;  meas- 
ure it  carefully,  and  write  the  volume  on  it  to  substi- 
tute for  "  10  c.  c."  if  it  differs.  The  graduate  is  ivet,  and 
the  salt  will  stick  in  it.  Results  of  careful  measuring 
will  be  about  100  c  c,  96  c.  c,  and  76  c.  c.  for  these  three 
trials. 

Experiment  4.— Are  there  spaces  between  them  for 
gas? 

Apparatus :  Flask  and  rubber  cork,  small  bottle  and 
good  cork,  cork  borer,  a  30  cm.  and  an  8  cm.  bit  of  glass 
tube,  30  cm.  rubber  tubing,  piece  of  marble  or  limestone 
size  of  hickory  nut,  5  cm.  squares  of  window  glass,  and 
some  dilute  hydrochloric  acid. 

A  wide  dish,  flat  bottomed  and  10  cm.  deep,  will 


THE  STUDY  OF  MOLECULES.  12Y 

be  needed  for  each  six  pupils  (pudding  dish  or  milk  pan), 
and  an  alcohol  lamp. 

There  is  so  much  new  to  the  pupil  in  this  experiment 
that  the  teacher  had  better  go  through  it  before  the  class 
first.    Proceed  as  follows : 

All  take  your  notebooks  and  write  what  I  tell  you  to 
write  while  showing  how  to  answer  this  question. 

1.  I  take  this  piece  of  marble,  wrap  it  in  a  number  of 
thicknesses  of  paper,  and  crush  with  this  hammer.  I 
now  open  the  torn  paper  over  a  whole  sheet,  and  pour 
the  marble  into  this  small  bottle.  Write:  "1.  Break 
marble  and  put  it  in  small  bottle." 

2.  I  light  the  alcohol  lamp,  and,  holding  the  middle 
of  this  8  cm.  piece  of  glass  tube  in  the  upper  part  of  the 
flame,  slowly  roll  it  around  so  as  to  heat  all  sides  equally. 
Now  it  begins  to  feel  flexible  in  the  middle,  and  I  slowly 
bend  it  to  a  right  angle  and  lay  it  on  this  board  to  cool. 
Why  not  lay  it  on  iron  or  cool  in  water  ?     (Break.) 

I  was  careful  not  to  twist  or  push  on  the  tube  while 
soft,  and  by  slowly  bending  before  it  got  red-hot  the  hole 
through  it  is  still  round  and  open.  Write :  "  2.  Bend 
8  cm.  tube." 

3.  I  take  this  sound  (solid  and  free  from  holes)  cork 
and  try  it  in  the  bottle  holding  the  marble.  It  fits.  I 
now  choose  this  cork  borer,  a  little  smaller  than  the  bent 
tube,  and  with  a  twisting  motion  push  it  slowly  through 
the  cork,  which  I  place  against  another  cork.  "  Why  ? " 
Watch  while  I  make  this  second  hole  half  an  inch  to 
one  side  of  the  first.  (Breaks  a  piece  out  as  it  comes 
through.)  Why  not  bore  against  this  hard  wood  or  a 
piece  of  iron  ?    (Dull  the  cork  borer.) 

In  one  of  these  holes  I  push  one  arm  of  my  bent  tube, 
which  I  first  soap  and  then  twist  in,  as  I  did  the  borer. 

Now  watch  while  I  cut  30  cm.  off  this  long  glass 
tube  for  a  "  safety  tube."  Having  measured,  I  take  this 
three-cornered  file  aad  draw  it  three  or  four  times  across 


128  SYSTEMATIC  SCIENCE  TEACHING. 

the  place,  making  a  nick.  Placing  my  thumbs  firmly  on 
either  side  of  the  mark,  I  give  a  quick  bend  to  the  tube 
and  it  snaps  squarely  ofiF  at  the  mark.  Soaping  my  safety 
tube,  I  twist  it  into  the  second  hole  far  enough  to  just 
clear  the  marble  in  the  bottle  when  the  cork  is  tightly  in. 
Now  I  stick  my  two  forefingers  into  the  end  of  this 
piece  of  rubber  tube  and  pull,  so  as  to  turn  a  little  of 
the  end  inside  out,  and,  pushing  this  inverted  end  against 
the  upper  end  of  my  glass  "elbow,"  slip  it  on  a  little  way. 
Write :  "  3.  Bore  two  holes  in  cork,  insert  elbow,  cut 
30  cm.  safety  tube  and  insert,  and  slip  rubber  tube  on 
'elbow.'" 

4.  These  rubber  corks  have  a  hole  which  we  do  not 
need  for  use  now.  To  close  tightly,  I  slip  in  any  solid 
round  thing  which  fills  the  hole  tightly  (bit  of  pencil, 
wood,  or  glass  rod).  Now  I  see  that  the  cork  fits  the 
mouth  of  this  flask.  It  does.  Write :  "  4.  Plug  hole  in 
rubber  cork  and  fit  to  flask." 

5.  I  half  fill  this  large  dish  with  water ;  fill  brimful 
the  flask  and  set  it  in  the  water,  while  I  pour  half  an  inch 
of  water  into  the  small  bottle,  covering  the  marble. 
Write :  "  5.  Fill  flask,  half  fill  dish,  and  put  half  an  inch 
of  water  on  the  marble," 

6.  I  take  this  square  of  clean  glass  and  lay  it  on  the 
top  of  the  brimming  flask.  A  little  air  bubble  shows 
under  it,  so  I  remove  and  pour  a  little  w^ater  into  the 
flask,  and  again  place  on  the  glass.  No  air  shows ;  so, 
holding  the  glass  in  place  w^ith  my  right  hand,  I  raise 
the  flask  with  my  left  and  turn  it  upside  down.  No 
water  can  run  out.  Still  holding  the  glass  in  place,  I 
lower  flask  and  all  till  the  mouth  is  entirely  below  the 
water  in  the  large  dish,  and,  slipping  off  the  glass,  stand 
the  flask  bottom  up.  Why  does  not  the  water  run  out  ? 
(See  Barometer  in  16,  Step  XV.)  Write :  "  6.  Invert  flask 
in  large  dish  of  water  and  hold  from  tipping." 

7.  John  may  hold  my  flask  while  I  pour  about  half  a 


THE  STUDY  OF  MOLECULES.  129 

teaspoonful  of  this  acid  on  the  marble  and  quickly  push 
the  cork  tightly  in  place.  See  the  bubbles  of  gas  come 
off.  Do  not  pinch  or  kink  the  rubber  delivery  tube  in  any 
way  while  you  dip  the  end  below  the  water  in  the  dish. 

The  bubbles  coming  freely  from  its  mouth  tell  me  all 
is  working  right,  and  the  safety  tube  prevents  danger  of 
an  explosion.  Now  I  slip  the  end  of  the  rubber  delivery 
tube  (as  it  is  called)  below  the  mouth  of  the  slightly 
tipped  flask,  and  the  bubbles  of  gas  rapidly  rise  to  the  top 
and  push  out  the  water.  The  flask  is  now  half  full  of  gas, 
and  removing  the  rubber  tube,  I  place  my  hand  under  the 
water  and  slip  in  the  rubber  cork  as  tightly  as  I  can  and 
not  break  the  flask.  Write :  "  7.  Put  half  a  spoonful  of 
acid  on  marble,  cork  tightly,  and  when  gas  is  coming  oflp 
freely  run  it  into  the  flask  till  half  the  water  is  pushed 
out.    Cork  under  water." 

8.  Keeping  the  corked  mouth  of  the  flask  down,  I  raise 
it  out  of  the  water  and  look  at  the  neck.  See  the  little 
bubbles  of  air  rising  through  the  water.  The  cork  is 
loose.  I  quickly  put  the  mouth  under  water  again  to  stop 
the  air  getting  in,  and  give  the  cork  a  twisting  push  to 
make  it  tight,  for  no  air  must  enter.  Trying  again,  no 
bubbles  show,  and  I  now  shake  the  flask  in  this  way  (vio- 
lently) for  a  whole  minute,  and  replace  the  mouth  at 
once  below  the  water  in  the  dish.  Keeping  the  mouth 
carefully  covered,  I  grasp  the  cork.  Now,  the  question 
is — what  ?  C'  Are  there  cracks  in  water  into  which  mole- 
cules of  gas  can  get  ? ")  Watch  the  surface  of  the  water 
in  the  flask  while  I  twist  out  the  cork.  (Water  rises !)  We 
will  not  discuss  this  now,  but  recork  the  flask  and  shake 
again.  (Rises  more.)  Try  still  a  third  time.  (Rose  again.) 
Write :  "  8.  See  that  no  air  enters  when  flask  is  removed 
from  the  water,  and  shake  one  minute.  With  the  mouth 
wholly  under  water,  watch  the  surface  in  the  flask  care- 
fully while  the  cork  is  slowly  twisted  out.  Recork,  and 
shake  again  twice." 
10 


130  SYSTEMATIC  SCIENCE  TEACHING. 

This  is  all  to-day.  To-morrow  all  try  this  and  write 
your  notes. 

Lesson  6. — Spend  not  over  five  minutes  in  a  brisk  re- 
view of  the  instructions  given  yesterday,  and  then  Jet  the 
class  go  to  work. 

Experiment  5.— Can  the  molecules  of  a  solid  be  forced 
nearer  together? 

Have  sixty  big  bullets  ready,  and  as  soon  as  some  of 
the  class  are  through  and  have  notes  written  let  them 
find  the  volume  of  the  bullets  as  follows : 

1.  Roll  or  drop  the  bullets  gently  into  an  inclined  and 
dry  graduate  (so  as  not  to  break  the  glass).  If  the  sixty 
pieces  rise  above  the  50  c.  c.  mark  in  one,  divide  them  be- 
tween two  graduates, 

2.  Measure  exactly  50  c.  c.  of  water,  if  bullets  are  in 
one,  or  100  c.  c.  if  in  two  graduates. 

3.  Pour  this  measured  water  on  the  bullets  till  covered, 
and  the  water  stands  exactly  at  the  50  c.  c.  mark.  How 
much  water  is  left  ?  (The  volume  of  the  lead.)  Record 
all  the  above. 

A  second  pair  of  pupils  (who  know  nothing  of  the  re- 
sults found)  may  now  roll  the  lead  in  a  towel  till  dry 
and  try  again.  Call  the  class  to  order  a  few  moments 
before  the  close  of  the  lesson.  Let  them  place  the  figures 
found  regarding  the  lead  under  the  head  of  Experiment 
5,  and  give  each  two  bullets  to  find  if  the  molecules  of 
a  solid  can  be  forced  nearer  together.  Caution  them  to 
pound  into  some  regular  shape  (cube  or  prism)  on  a  clean 
iron  surface,  and  to  pound  hard,  and  return  them  to-mor- 
row to  see  if  they  measure  less. 

Lesson  6. — Experiments  3  and  4  have  now  been 
tried.  Gather  the  pounded  bullets  and  measure  again 
for  the  class  to  complete  the  notes  regarding  (5),  which 
should  be  as  follows : 

1.  Sixty  bullets  measured,  say,  39  c.  c.  =  .65  c.  c.  in  each. 

2.  Pounded  each  one  hard  on  clean  surface. 


THE  STUDY  OF  MOLECULES.  131 

3.  Sixty  pounded  bullets  measured  37^  c.  c.  =  .625  c.  c. 
in  each ;  .65  —  .625  =  .025  c.  c.  loss  in  bulk. 

Yes,  the  molecules  of  lead  can  be  forced  closer. 

Experiment  has  now  proved  that  liquids  (alcohol), 
and  gas  (COa)  can  find  their  way  among  the  molecules 
of  water,  and  that  solids  can  be  compressed  (lead). 

Does  this  answer  the  question  of  Lesson  4  ? 

(Molecules  do  have  spaces  between  them.) 

Do  all  molecules  seem  to  be  of  the  same  size  ?  (No,  for 
alcohol,  gas,  and  salt  could  get  between  those  of  water.) 

Illustrate  this  by  the  following  story  of 

THE  REMARKABLE  BARREL  OF  APPLES. 

A  grocer  bought  a  barrel  of  very  large  and  sound  ap- 
ples, and,  removing  the  top  cover,  placed  it  in  front  of 
his  store  to  attract  buyers.  Who  can  teU  me  just  how  it 
looked  ? 

Yes,  they  were  rosy  and  smooth,  a  few  top  ones  were 
slightly  flattened,  and  between  them  were  crevices,  al- 
though all  touched  and  were  still. 

As  the  barrel  stood  there  a  man  came  out  with  a  pa- 
per bag  of  beans  and  laid  it  on  the  apples.  On  picking 
it  up  the  bottom  gave  way,  and  out  spilled  the  beans  on 
the  apples. 

As  he  went  back  into  the  store  for  another  bag,  some 
men  who  stood  by  decided  to  play  a  joke,  and  shook  the 
apple  barrel  till  the  beans  had  almost  disappeared.  The 
man  complained  to  the  storekeeper  that  he  had  lost  his 
beans,  and  wanted  to  empty  out  the  apples  and  get  them  ; 
but  he  refused,  as  he  said  handling  injured  the  apples, 
and,  gathering  up  what  lay  on  top,  gave  the  man  some 
more.  Soon  after  a  child  came  out  with  arms  full  of 
bundles,  and  finding  they  were  in  danger  of  falling, 
tried  to  drop  them  on  the  apples.  One  package  fell 
heavily,  and  out  burst  a  lot  of  granulated  sugar. 

The  mischief-making  men  were  standing  by,  and,  as 


132  SYSTEMATIC  SCIENCE  TEACHING. 

the  child  went  in  to  tell  the  storekeeper,  slyly  shook  the 
barrel  till  the  sugar  had  almost  disappeared.  Where  ? 
The  grocer  was  much  displeased,  and  scolded  the  child 
for  making  ''  a  sweet  mess  of  his  apples,"  and  wanted  her 
to  go  home  without  her  sugar ;  but  the  jokers  were  brave 
enough  to  tell  of  their  part  in  the  matter,  and  offered  to 
•pay  for  the  sugar  if  they  might  see  if  anything  else  could 
be  got  into  that  barrel.  What  else  would  go  in  do  you 
think  ?  Yes,  they  tried  water,  and  poured  in  quite  a 
quantity  before  the  barrel  was  really  full.  Even  then 
one  of  them  said,  "  That  barrel  is  not  full  yet ! "  Most 
of  the  crowd  laughed  at  the  idea  of  getting  anything 
more  in.    Would  you  have  done  so  ? 

At  last  one  man  said  he  would  pay  the  cost  if  any- 
thing bigger  than  a  pin  could  be  got  in.  So  the  man 
who  said  the  barrel  was  not  full  tried — what  ? 

Yes,  he  brought  a  jug  of  alcohol,  and,  by  adding  a 
little  at  a  time,  really  put  in  quite  a  quantity. 

At  last  it  would  hold  no  more,  and  most  supposed 
that  barrel  was  full.  But  a  chemist  who  stood  by  said, 
'•  Not  yet.  I  can't  show  you  with  that  open  barrel,  but 
will  show  how  it  could  be  done  with  this  bottle  of  water ; " 
and  really  did  so.  What  did  he  do  ?  ("Dissolved  gas.'*) 
Just  as  we  did!  True  enough.  This  barrel  of  apples 
helps  us  to  understand  how  a  thing  can  be  full  of  one 
tiling  and  still  have  room  for  more  of  something  else_ 
But  there  are  two  things  about  the  apples  very  unlike  the 
molecules  of  this  water  or  lead  ;  for  we  have  good  reason 
to  think  the  molecules  neither  touch  nor  axe  stilL 

A  book  I  am  much  indebted  to,  by  Mr.  Stewart,  of 
England,*  illustrates  this  by  the  stars,  sun,  and  planets. 

After  speaking  of  the  Milky  Way  and  its  myriad 
stars,  of  our  sun.  the  nearest  star,  and  its  planets  and 
their  moons,  he  uses  these  words :  "  Now,  just  as  in  the 

*  Elementary  Physics,  p.  2. 


THE  STUDY  OP  MOLECULES.  133 

starry  firmament  there  are  vacant  spaces  between  the  va- 
rious individual  stars,  so  in  the  small  scale  there  are 
probably  vacant  spaces  between  the  various  molecules 
of  a  body." 

So  I  want  you  all  to  think  of  the  molecules  of  glass 
in  this  tumbler,  or  of  steel  in  this  knife,  as  separated  on 
all  sides  from  each  other,  just  as  the  earth,  moon,  and 
sun  are,  and  hence  with  plenty  of  room  to  move  in. 

To  further  illustrate,  let  me  draw  these  dots  on  the 
board ;  the  spaces  between  them  are  much  larger  than 
the  dots  themselves.  I  know  what  you  want  to  ask,  and 
to-morrow  we  will  try  and  find  how  it  happens  that  the 
glass  and  lead  are  not  shapeless  heaps  of  molecules. 

Lesson  7. — A  brisk  review  of  the  lessons  so  far  ;  then 
proceed. 

We  find  molecules  very  small,  probably  round,  of  dif- 
ferent sizes  in  different  things  (the  same  size  in  each),  and 
that  they  do  not  touch  each  other. 

The  next  question  is.  What  holds  them  together  ?  We 
have  many  sets  of  words  which  express  difl'erent  states 
or  degrees  of  the  same  thing.  We  say  "  a  breath,"  "  a 
breeze,"  "  a  gale,"  "  a  tempest,"  of  wind.  So  we  use  the 
words  "  touch,"  "  tap,"  "  slap,"  "  blow,"  to  tell  how  a  thing 
came  against  us.  Again  we  say,  ''The  flowers  attract 
bees,"  "The  child  draws  his  wagon,"  "The  lion  fwgrs  at 
his  chain."  So  we  have  various  words  for  the  force  or 
forces  (for  we  are  not  sure  they  are  the  same  thing) 
which  try  to  hold  molecules  together,  and  we  will  ex- 
periment about  two  to-day.  Push  your  experimenting 
vigorously  and  we  can  finish  both.  (Give  cards  and  ma- 
terial.) 

Experiment  6.— Cohesion  binds  molecules  of  the  same 
kind. 

Try  to  stick  two  pieces  of  chalk  together. 

Two  pieces  of  dry  glass. 

Two  pieces  of  bright  lead. 


13J:  SYSTEMATIC  SCIENCE  TEACHING. 

Two  pieces  of  clay  (moist). 

Two  pieces  of  cold  wax. 

Warm  the  wax  and  try. 

The  force  which  holds  molecules  of  the  same  kind 
together  is  called  cohesion. 

Does  it  act  at  long  distances,  or  short  ? 

Record  other  examples. 

When  Experiment  6  is  complete,  give 

Experiment  7.— Adhesion  binds  molecules  of  different 
kinds. 

Try  to  shake  a  lead  pencil  mark  off  a  piece  of  paper. 

Wet  two  pieces  of  glass  and  see  if  they  stick  to- 
gether. 

Dip  a  glass  tube  in  water,  and,  holding  it  up,  write 
what  you  see. 

The  force  which  holds  different  molecules  together  is 
called  adhesion. 

Does  it  act  at  long  distances  ? 

Give  other  examples  of  adhesion,  and  record. 

Lesson  8. — A  two-minutes  review  of  yesterday.  There 
is  a  third  force  tending  to  draw  things  together,  which 
we  will  learn  more  about  to-day. 

Experiment  8.— Gravitation  draws  all  things  together. 

Lift  some  lead  1  cm.  and  let  go. 

1  M.  and  let  go. 

As  high  as  you  can  and  let  go. 

Repeat  with  two  other  substances. 

What  did  they  do  at  all  distances  ? 

The  force  which  causes  this  is  called  gravitation. 

Record  other  examples.    (See  Step  XXX.) 

To  test  this  still  further,  and  see  whether  it  acts  on 
air  and  water  as  well  as  the  things  you  have  tried,  sus- 
pend your  30  c.  c.  bottle  by  a  fine  wire  1  m.  long  (meas- 
ure from  the  center — inside — of  the  bottle  to  the  screw 
the  wire  is  fastened  to).  Set  it  swinging  from  side  to 
side,  and  count  the  number  of  times  it  passes  the  center 


THE  STUDY  OF  MOLECULES.  135 

in  one  minute.  Prove  by  counting  again.  We  call  such 
a  thing  a  pendulum. 

What  makes  it  swing  ?  What  is  the  bottle  filled 
with  ? 

Now  fill  (without  untying  from  the  screw,  lest  you 
change  the  length)  with  lead  and  count  twice. 

Fill  with  sand  and  count  twice. 

Fill  with  water  and  count  twice. 

Lesson  9. — What  are  the  three  forces  (as  we  call  them) 
found  trying  to  keep  molecules  together  ?  (Cohesion,  ad- 
hesion, gravitation.) 

Which  act  at  short  distances  only  ? 

Which  at  all  distances  ? 

Which  between  like  molecules  ?  Unlike  molecules  ? 
All  molecules  ? 

What  is  a  pendulum  ?  What  makes  it  swing  ?  (Gravi- 
tation.) 

How  do  you  find  the  length  (center  of  weight  to  at- 
tachment) ? 

Kate  and  Mary  may  give  me  their  counts  to  place  on 
the  board. 

1.  Full  of  —  ?  (air)  =  1 1  -j°g  I  average  =  60 
swings,  or ?    (Vibrations.) 

2.  F 
swings, 

3.  F 
swings 


2.  Full  of  ?  (lead)  =  ]  ^9  swing  |  ^^^^^^^  ^  gg 


3.  Full  of ?  (sand)  =  \  «»  ^^!°g  \  average  =  60 

ings 

4.  Full  of ?  (water)  =  |  f^  ^^°g  |  average  =  59^ 

swings. 

What  do  you  notice  about  these  averages  ?  (Nearly 
alike.) 

Yes,  as  nearly  as  can  be  expected,  with  our  appa- 
ratus. 


136  SYSTEMATIC  SCIENCE  TEACHING. 

What  do  you  infer  from  this  ?  (All  things  fall 
equally  fast.) 

Which  way  do  they  fall  ?  (Straight  toward  the  cen- 
ter of  the  earth.) 

What  forces  are  acting  on  ray  ink  bottle  ?  (Cohesion 
holds  glass  molecules  in  shape,  adhesion  holds  label  and 
ink  stains,  and  gravitation  makes  it  press  on  the  hand 
that  holds  it.) 

(Multiply  such  questions,  for  the  subject  is  far-reach- 
ing.) 

To-morrow  we  will  see  the  results  of  weak  or  strong 
cohesion  and  adhesion. 

Lesson  10. — Omit  review.  Give  Experiments  9,  10, 
and  11. 

Experiment  9. — Try  to  twist,  stretch,  and  squeeze  to- 
gether a  piece  of  wood  or  iron. 

Does  it  keep  its  shape  ? 

Has  it  any  hardness  ? 

Such  a  thing  is  called  a  solid. 

Write  about  this,  and  name  five  other  solids. 

Experiment  10.— Take  100  c.  c.  of  water  and  pour  it 
into  four  different  shaped  dishes. 

Does  it  fit  each  one  equally  well  ? 

What  kind  of  a  surface  has  it  in  each  ? 

Has  it  any  hardness  ? 

Such  substances  are  called  liquids. 

Name  five  others  in  your  notes. 

Experiment  11.— Push  an  "empty"  bottle,  mouth 
down,  into  some  water. 

Why  does  not  the  water  enter  ? 

Has  air  any  shape  ? 

Any  level  surface  ? 

Any  hardness  ? 

Does  it  stick  to  things  ? 

Does  it  seem  to  have  any  cohesion  ? 

Such  things  we  call  gases. 


THE  STUDY  OF  MOLECULES.  137 

Heat  your  flask  hot,  drop  in  a  crystal  of  iodine,  and 
see  how  the  violet  vapor  fills  the  flask. 

Lesson  11.— How  would  you  know  a  solid  ?  (Hard- 
ness and  shape.) 

How  know  a  liquid  ?  (Level  surface,  and  always  fits 
containing  vessel.) 

How  know  a  gas  ?  (Molecules  fly  apart,  and  fill  any 
containing  vessel,  no  matter  how  large.  Has  no  level 
surface.) 

Which  of  these  has  the  strongest  cohesion  ?     (Solid.) 

Do  liquids  have  cohesion  ?  (A  little,  as  shown  by 
drop  of  water.) 

What  held  the  drop  to  the  glass  tube  ?    (Adhesion.) 

Why  did  the  water  rise  higher  inside  the  tube  ?  (Ad- 
hesion acting  on  all  sides  of  a  small  surface  raised  it.) 

What  forces  pulled  the  water  down  in  the  center  ? 
(Cohesion  and  gravitation.) 

In  which  of  the  three  classes  did  the  molecules  seem 
freest  to  move  ?     (Gas.) 

In  which  were  they  most  fixed  ?    (Solid.) 

What  was  the  intermediate  stage  called  ?    (Liquid.) 

By  these  experiments  I  have  tried  to  give  you  the  idea 
of  the  tiny  molecules  separated  from  each  other  by  spaces 
and  still  held  from  getting  clear  away  by  these  forcas. 
What  the  forces  are  (or  is^  for  there  are  many  reasons 
for  thinking  the  three  really  only  one)  which  reach  across 
all  spaces  from  the  tiny  ones  between  the  molecules  which 
cohesion  can  span  to  the  enormous  distance  between  the 
sun  and  his  planets,  I  have  nothing  to  tell  you,  for  no 
one  knows.  Perhaps  some  of  you  may  be  wise  enough 
to  find  out  in  the  future.  Meanwhile,  let  us  ask  Nature 
another  question  about  these  wonderful  molecules :  Are 
they  still,  or  in  motion? 

Experiment  12.— Make  a  pendulum  of  a  bullet  and 
thread. 

See  it  swing  back  and  forth. 


138  SYSTEMATIC  SCIENCE  TEACHING. 

Each  swing  is  called  a  vibration. 

Make  it  vibrate  in  a  circle. 

Take  a  "  return  ball "  and  see  how  it  vibrates  up  and 
down. 

What  are  three  ways  a  thing  can  vibrate  ? 

Lesson  12. — Here  is  a  ball  on  my  desk.  Unless  some- 
thing moves  it,  how  long  will  it  stay  there  ?    (Forever.) 

Suppose  I  threw  it  hard  into  some  mud  ?  (Stopped 
by  mud.) 

If  I  threw  it  to  another  boy  and  he  failed  to  catch  it  ? 
(Strike  the  ground.) 

If  thrown  up,  what  force  (that  we  have  talked  of) 
would  stop  it  ?     (Gravitation.) 

Do  you  know  of  any  case  where  it  would  not  stop  ? 
(No.) 

If  the  ball  got  started  and  there  was  nothing,  to  stop 
it,  how  long  would  it  keep  going  ?    (Forever.) 

Hence  we  must  conclude  that  nothing  starts  or  stops 
unless  made  to  do  so.  Now,  molecules  are  "  things  "  just 
as  much  as  this  ball,  and  if  "  still "  it  must  be  because 
they  have  never  started,  or  have  been  stopped.  If  in  mo- 
tion, it  is  because  something  has  set  them  going. 

What  do  you  call  the  act  of  a  man  who  keeps  a  spade 
from  "  stopping  "  all  day  ?    (Work.)     Another  man  starts 

a  pen  and  keeps  that  going,  he  ?     (Works.)      A 

woman  keeps  the  dust  flying  with  her  broom  ?  (Works.) 
A  man  pitches  bricks  to  another  ?  (He  works  to  keep  up 
motion.)  How  about  the  man  that  catches  the  bricks  ? 
(Works  to  stop  motion.)  So  we  might  add  many  illus- 
trations to  show  that  all  work  causes  a  change  from  rest 
to  motion  or  motion  to  rest. 

Let  us  try  some  experiments,  and  see  what  work 
can  do. 

Experiment  13. — Toss  something  up  and  catch  it  again. 

Repeat  three  times,  and  then  write  what  work  you 
did  and  what  came  from  it. 


THE  STUDY  OF  MOLECULES.  139 

Experiment  14.— Pound  a  piece  of  lead  hard,  and, 
touching  it  to  your  lips,  write  the  result  of  your  work. 

Do  the  same  with  a  nail. 

Experiment  15.— Hold  a  shoe  button  on  a  thread  near 
a  bell  and  gently  tap  the  other  side. 

What  happens  ? 

Tap  a  tuning  fork  on  the  table  and  touch  the  prongs 
to  the  button. 

Stretch  a  piece  of  India-rubber  string  and  make  it 
sound  by  pulling  the  middle  to  one  side  and  then  letting 
it  go. 

Watch  it. 

Write  what  you  saw  in  each  case. 

Did  you  do  work  ? 

What  was  the  effect  ? 

Experiment  16. — Rub  a  match  head  quickly  across  a 
rough  surface.    What  did  you  get  for  your  work  ? 

Lesson  13. — Alice  may  read  her  notes  on  Experiment 
13.  "  I  set  the  ball  in  motion  and  stopped  it  again.  For 
my  work  I  got  motion  and  rest." 

What  stopped  it  when  going  up  ?     (Gravitation.) 

Did  any  one  get  something  else  from  his  experi- 
ment ? 

James  :  "  I  think  I  moved  the  air."    Yes ! 

Thomas :  "  I  got  sound  when  it  hit  my  hands." 

Charles  may  read  about  14.  "  I  did  work  in  hammer- 
ing, and  got  heat  and  change  of  shape." 

Mary :  "  I  also  got  noised 

Ralph :  "  The  lead  changed  shape  the  most,  and  the 
iron  got  the  hottest." 

Samuel  may  read  his  notes  on  15.  "I  held  the  button 
near  the  bell  and  struck  the  other  side.  The  button 
danced  out  and  back  as  the  bell  sounded.  The  tuning 
fork  sounded  and  made  the  button  fly  off.  The  rubber 
sounded  and  seemed  to  fly  from  side  to  side.  I  did  work 
in  each  case,  and  got  sounds 


140  SYSTEMATIC  SCIENCE  TEACHING. 

Very  good.  Now  Henry  may  read  his  notes  on  the 
match. 

"  Rubbed  a  match,  and  got  sound,  light,  and  heat." 
Yes. 

They  say  that  when  the  Government  is  testing  its  can- 
non the  huge  steel  shot  are  fired  against  a  strong  target 
covered  with  iron  plates.  When  the  swiftly  moving 
shot  crashes  against  the  target  and  is  stopped  and  bat- 
tered a  flash  of  flame  is  seen. 

What  made  the  shot  go  ?    (Powder.) 

What  work  did  it  do  ?  (Changed  shape  of  itself  and 
target,  made  heat,  flame,  and  sound.) 

To-day  we  will  try  another  way  of  changing  the  con- 
dition of  molecules. 

Experiment  17.— 1.  Dip  a  magnet  into  a  box  of  iron 
filings,  and,  lifting  it  out,  write  what  you  see. 

2.  Replace  all  the  filings.  Place  the  head  of  a  large 
tack  against  the  magnet,  and  then  let  the  end  of  it  touch 
the  filings.  Raise  and  observe  ;  then  carefully  take  hold 
of  the  large  tack  and  slide  its  head  off  the  magnet.  What 
happens  ?  * 

3.  Take  a  large  steel  needle  that  has  never  touched 
a  magnet  and  dip  it  among  some  iron  filings.  Do  any 
adhere  ?  Then  stroke  the  unmarked  end  of  the  magnet 
with  the  pointed  end  of  the  needle  (as  in  5,  Step  XXV) 
ten  to  twenty  times,  and  try  again. 

4.  Suspend  your  needle  by  a  long  thread  tied  about 
the  middle,  and  let  it  come  to  rest.  Which  way  does  the 
eye  end  point  ? 

5.  While  waiting  for  the  big  magnet  to  get  still, 
choose  a  cork  which  will  float  upright  in  the  water,  lay 
the  needle  on  its  top  or  run  it  through  the  cork  so  as  to 
be  parallel  to  the  surface  of  the  water. 

*  Teacher  must  be  sure  the  tacks  and  filings  are  not  steely 
which  is  frequently  used  nowadays. 


THE  STUDY   OF  MOLECULES.  141 

Set  this  afloat,  and  see  which  end  points  the  same  way 
as  the  marked  end  of  the  large  magnet,  and  mark  it  by 
slipping  on  a  bit  of  red  paper.  We  now  know  which 
ends  of  our  two  magnets  are  alike  and  which  are  opposite. 

6.  Bring  the  like  ends  of  the  large  and  floating  mag- 
nets near  (must  not  touch)  each  other,  and,  after  repeated 
trials  with  botli  marked  and  unmarked  ends,  write  your 
observations. 

7.  Now  reverse  the  6th,  and  bring  unlike  ends  near  in 
the  same  way. 

8.  Break  the  needle  in  the  middle,  and,  mounting  one 
piece  in  the  cork,  use  the  other  as  the  larger  magnet  in 
6  and  7.  Have  you  two  half  magnets,  or  two  smaller 
whole  ones  ? 

Lesson  14. — Review  yesterday's  work  with  magnets. 

What  does  a  magnet  do  to  iron  filings  ?     (Picks  up.) 

Do  the  iron  filings  seem  to  be  magnetized  when  on 
the  magnet  ?    (Yes,  for  others  hang  to  them.) 

Do  they  keep  this  magnetism  after  being  removed 
from  the  magnet  ?  (No.  A  big  tack  held  filings  till  it 
slipped  off  of  the  magnet,  and  then  they  soon  fell.) 

What  are  needles  made  of  ?    (Steel.) 

Did  tlie  needle  pick  up  iron  filings  before  it  touched 
the  magnet  ?     (No.) 

Tell  me  exactly  how  you  magnetized  it.  (Stroked  the 
unmarked  end  of  the  magnet  with  the  pointed  end  of  the 
needle.) 

How  do  you  know  that  made  a  magnet  of  the  needle  ? 
(Picked  up  filings,  always  pointed  north  and  south,  and 
acted  like  the  large  magnet  when  brought  near  it.) 

You  made  the  marked  end  of  the  needle  by  stroking 
which  end  of  the  magnet  ?     (Unmarked.) 

Suppose  you  had  wanted  the  eye  of  the  needle  to  point 
north  f     (Would  have  rubbed  that  on  the  unmarked  end.) 

Then  the  new  magnet  is  just  the  opposite  of  the  end 
stroked. 


142  SYSTEMATIC  SCIENCE  TEACHING. 

How  do  these  unlike  ends  behave  toward  each  other  ? 
(Attract.) 

How  did  you  prove  it  ?  (By  drawing  the  cork  and  its 
needle  about  in  the  water.) 

How  do  like  ends  behave  ?     (Repel.) 

How  wonderful  that,  without  touching^  a  thing  can 
be  pulled  and  pushed  I 

On  breaking  the  needle  did  you  get  two  halves,  or  two 
small  magnets  ?    (Two  small  magnets.) 

How  did  you  prove  it  ?  (One  half  pointed  north  and 
south,  and  the  other  drew  and  repelled  it,  just  as  the  large 
magnet  did.) 

All  these  wonderful  things  we  believe  are  due  to  an 
arrangement  of  the  molecules  in  the  iron  or  steel. 

In  which  does  this  arranging  only  last  while  the  mag- 
net is  near  or  touches  ?     (Iron.) 

And  steel  ?  (The  molecules  stay  as  the  magnet  fixed 
them.) 

There  is  another  way  the  molecules  can  be  changed, 
which  we  will  show  by  experiment  to-day. 

Experiment  18.— Electricity. 

1.  Hang  a  ball  of  pith  by  a  silk  thread  from  the  end 
of  your  longest  glass  rod. 

2.  Rub  a  hard-rubber  comb  or  ruler  briskly  on  some 
fur  or  woolen  ;  bring  it  to  the  ball,  and  after  three  trials 
record  what  you  saw. 

3.  Rub  a  large  glass  rod  or  tube  (Argand  chimney) 
briskly  with  old  silk,  and  bring  it  to  the  ball.  Repeat 
twice  and  record. 

4.  One  rub  the  glass,  while  the  other  rubs  the  rubber 
comb,  and  present  both  to  opposite  sides  of  the  ball  for  a 
minute.     Record. 

5.  Place  a  pinch  of  light  chaff  or  bran  in  a  box  cover 
about  15  mm.  deep.  Set  this  on  a  bare  table,  cover  with 
a  piece  of  clean  and  dry  window  glass,  and  rub  briskly 
with  the  silk  over  the  chaff.     Record. 


THE  STUDY  OF  MOLECULES.  143 

6.  Rub  the  comb  and  hold  it  near  the  chaff. 

Lesson  16. — When  hard  rubber  is  rubbed  on  fur  or 
woolen,  what  can  it  do  ?  (Pick  up  light  things  and  at- 
tract and  repel  pith  ball.) 

When  glass  is  rubbed  with  silk  ?  (Chaff  keeps  flying 
up  to  the  glass  and  back  to  the  box,  and  it  attracts  and 
repels  pith  ball.) 

We  call  the  glass  and  rubber  "  electrified  "  when  they 
do  this. 

Did  the  pith  ball  stick  quietly  to  the  rubber  or  glass  ? 
(No ;  after  first  touching,  it  was  repelled.) 

What  happened  when  both  were  presented  to  the  pith 
ball  ?     (It  vibrated  from  one  to  the  other.) 

Jane  may  read  her  notes  on  the  5th.  "The  chaff 
danced  up  and  down,  from  the  box  to  the  glass  and  back. 
Some  stuck  to  the  glass  a  moment." 

Mary  may  read  about  6.  "  The  rubbed  comb  picked 
up  the  chaff  and  held  it  quite  a  while." 

Did  any  one  see  what  it  was  that  pulled  and  pushed 
the  ball  and  chaff  ?     (No.) 

When  the  magnet  touched  a  tack  what  did  it  do  to  it  ? 
(Magnetized  it.) 

When  the  electrified  comb  touched  the  ball,  what 
happened  to  it  ?    (Was  electrified.) 

We  had  two  kinds  of  magnetism  (at  the  two  poles). 
Have  the  experiments  taught  you  whether  there  are  two 
kinds  of  electricity  ?  (Yes ;  that  in  glass  drew  the  ball, 
that  in  rubber  repelled.)     Correct. 

We  call  that  in  glass  '*  +,"  and  that  in  rubber  (or 
sealing  wax)  "  — ." 

Who  can  tell  me  ways  in  which  magnetism  and  elec- 
tricity resemble  each  other  ? 

"  Two  kinds  :  +  from  glass  and  —  from  rubber." 

Like  kinds  repel  each  other  (ball  thrown  off  and  chaff). 

Unlike  kinds  attract  (pith  ball  between  two  kinds). 

Both  act  in  an  unseen  way  across  quite  a  space. 


144  SYSTEMATIC  SCIENCE  TEACHING. 

One  more  thing  I  want  you  to  get  for  work. 

Experiment  19.— Rub  your  hands  together  hard. 
What  did  you  get  ? 

Rub  a  metal  button  or  coin  on  a  woolen  cloth.    What  ? 

Find  and  record  answers  to  at  least  two  of  the  follow- 
ing questions : 

1.  Why  are  your  hands  blistered  by  sliding  down  a  rope  ? 

2.  How  did  the  natives  of  north  Asia  get  fire  before 
having  matches  or  stfeel  ? 

3.  How  did  Gitche  Manito  light  the  "  peace  pipe  "  in 
Hiawatha  ? 

4.  Why  does  a  man  throw  water  on  the  wheel  over 
which  the  rope  attached  to  the  harpoon  in  a  whale 
rapidly  runs  out  ? 

5.  How  does  a  saw  or  an  auger  bit  feel  after  going 
through  a  hard  board  ? 

6.  Why  do  we  oil  the  axles  of  cars,  wagons,  and  ma- 
chines ? 

Was  some  kind  of  work  done  in  each  of  these  cases  ? 

Lesson  16. — Kate,  what  did  you  get  by  rubbing  your 
hands  ?     (Noise,  worn  skin,  and  heat.) 

Robert,  you  rubbed  the  button  ?  (Wore  metal  and 
cloth ;  heat.) 

Who  has  an  answer  to  the  first  question  ?  (Samuel : 
"The  rope  heated  the  hands.") 

The  second  ?  (Jane  :  "  The  Chukches  had  a  fire  drill  " ; 
others  rubbed  dry  wood  together.)  (See  Voyage  of  the 
Vega,  pp.  311  and  312.) 

How  was  the  "  peace  pipe  "  lit  ?  (Susan  reads  selec- 
tion from  Hiawatha.) 

The  whale-boat  line  ?  (Edward  :  "  The  whale  sounds 
so  rapidly  when  struck  that  the  rope  might  set  the  boat 
on  fire.") 

Who  has  tried  the  saw  ?     (Paul :  "  It  was  hot.") 

And  the  bit,  or  auger  ?  (Peter :  "  Almost  burned  my 
fingers.") 


THE  STUDY  OF  MOLECULES.  145 

Why  do  we  oil  bearings  ?    (Mary  :  "  Would  grow  hot 

from  friction."") 

Was  work  done  in  each  case  ?    (Yes.) 

What  was  obtained  in  every  case  ?     (Heat.) 

We  must  not  linger  longer  over  this  ;  so  now  tell  me 

what  things  we  have  had  in  exchange  for  work  f 

1.  Change  of  place. 

2.  Change  of  shape. 

3.  Sound. 

4.  Light. 

5.  Magnetism. 

6.  Electricity. 

7.  Heat. 

In  which  can  the  eye  see  the  change  ?  (1,  2,  and 
partly  in  3.) 

What  did  sound  seem  to  be  caused  by  ?  (A  quivering 
motion.) 

Let  me  give  you  an  illustration  of  what  happens 
when  this  quivering  or  vibrating  becomes  more  rapid. 
Let  us  imagine  a  powerful  engine  in  the  basement  of 
a  tall  building.  Connected  with  it  is  an  iron  shaft 
running  up  to  the  middle  of  the  top  floor  (beyond  all 
sound  from  the  engine),  and  in  the  end  is  fixed  a  hori- 
zontal rod  half  a  metre  long,  A  strong  railing  pre- 
vents any  one  getting  in  the  way  of  this  rod,  as  it 
swings  round  and  round.  Holding  a  light  switch  in 
our  hands  to  feel  the  rod  as  it  swings  past  us,  we  stop 
the  machinery,  and  when  all  is  still  make  the  room 
perfectly  dark  and  quiet.  A  secret  signal  is  given  to 
start  the  rod  in  revolution  ;  once  the  first  second,  two 
times  the  second,  three  times  the  third,  and  so  on  up 
to  any  required  speed. 

How  could  we  know  the  rod  had  started  ?  (Feel  a 
blow  to  switch.) 

These  blows  would  grow  more  and  more  rapid,  and, 
laying  aside  our  switches,  we  wait  in  silence.  Every 
11 


146  SYSTEMATIC  SCIENCE  TEACHING. 

time  the  rod  went  round  it  would  push  the  air  away,  and 
we  might  possibly  feel  the  puffs  of  wind,  and  could  count 
them,  "  1,  2,' 3,  4,"  etc. ;  but  when  they  reached  16  per  sec- 
ond we  should  know  of  the  rod's  motion  in  another  way. 
You  have  heard  a  thrashing  machine  or  planing  mill. 
As  the  cylinder  or  saw  began  to  move,  we  first  heard  a 
low  grumble,  rising  higher  and  higher  as  the  speed  in- 
creased to  a  shrill  pitch,  falling  when  a  bundle  of  grain 
or  a  board  was  put  in,  to  quickly  rise  again  as  that  piece 
of  work  was  done,  and  another  bundle  or  board  pre- 
pared. So  with  our  rod.  We  should  at  16  vibrations 
(or  revolutions)  per  second  begin  to  hear  a  low  note, 
which  would  rise  higher  and  higher  till  the  shrill  sound 
was  almost  unbearable,  and  then  ?    (Silence.) 

Yes;  our  ears  can  not  hear  above  a  certain  number 
of  vibrations  per  second  ;  but  already  another  sense 
is  beginning  to  be  touched,  and  while  the  increasingly 
rapid  blows  can  not  be  heard,  we  can  feel — what  do  you 
suppose  ? 

Yes,  heat.  As  the  rod's  speed  increases  the  heat  be- 
comes greater  and  greater  till  another  sense  is  acted 
upon,  and  we ?    (See.) 

Have  you  ever  observed  a  piece  of  iron  get  hot  ?  It 
is  "  black  hot "  at  first,  then  comes  a  faint  red,  growing 
into  yellow,  and  at  last  "white  hot."  Our  rod  would 
pass  with  the  increasing  vibrations  from  heat  to  a  red ; 
then  passing  into  orange,  yellow,  and  white.  The  speed 
now  would  be  terrific  ;  seven  hundred  trillions  or  more 
per  second  representing  numbers  totally  beyond  our 
imagination,  and  no  real  machine  or  rod  could  ever 
reach  it.     But  our  imaginary  one  can. 

No  sound,  no  heat,  no  light  that  we  can  know  any- 
thing of.  But  had  we  a  camera  in  the  room,  the  rapid 
vibrations  could  still  take  a  photograph  of  our  astonished 
faces. 

I  have  told  you  this  to  help  you  to  understand  what 


THE  STUDY  OF  MOLECULES. 


147 


heat  and  light  are  supposed  to  be — simply  a  kind  of 
motion  of  the  molecnles. 

Lesson  17. — When  you  did  work,  did  you  always  get 
something  for  it  ?    (Yes.) 

Now  a  very  important  question.  If  work  does  one 
thing",  can  it  at  the  same  time  do  as  much  of  something 
else  ?    Think  of  this  carefully  before  you  answer. 

Let  us  place  our  experiments  in  a  table  on  the  board 
and  see.    Each  tell  me  of  one  thing  in  a  scale  of  ten. 


Experiment. 

Motion. 

Rest. 

Sound. 

Change 

of 
shape. 

Heat 

Light. 

Mag- 
net- 
ism. 

Elec- 
tric- 
ity. 

Ball  tossed 

Ball  caught .... 

10 

9 
"6 

1 
1 
2 

9 

8 
1 
1 
1 

7 
5 

1 
'  "l" " 

1 
2 

4 
1 
1 

3 

1 
1 

5 

8 

2 
2 

Lead     pounded 
Iron  pounded  . 
Bell    and    fork 

struck 

Rubber       cord 

pulled 

Match  rubbed  . 
Cannon  fired  . . 
Tarsret  struck 

1 
1 

1 

2 

1 
7 

Magnet  -  raised 
nails 

5 

1 

8 
8 

2 

2 

1 
1 
3 
3 
6 
2 
2 

6 

Magnet  stroked 
by  needle 

Unlike  poles  at- 
tract   

1 

Like  poles  repel 
Rubbed  comb  .. 

.... 

1 

1 
1 
1 
1 

1 
1 

1 
1 

1 

"  V  * " 

1 
1 
1 

"  *5  * ' 
5 

1 

2 

3 
7 
7 
5 
4 
3 
2 
2 

2 

5 

Rubbed      glass 
rod 

4 

Rubbed  hands  . 
Rubbed   button 
Climbed  rope  .. 

Fire  drill 

Whale  in  diving 
Sawed  board  . . 

Bored  hole 

Steam  -  moved 
cars 

1 

148  SYSTEMATIC  SCIENCE  TEACHING. 

Do  not  compare  one  experiment  with  another,  for  the 
same  amount  of  work  was  not  done  in  each  case.  What 
shall  we  conclude  ?  (No  ;  when  work  does  one  thing  it 
can  not  be  doing  something  else.) 

Let  the  teacher  fully  illustrate  this  far-reaching  and 
important  principle  of  the  conservation  of  energy  by 
talking  of  purchases  with  money  (if  we  buy  one  thing, 
we  must  give  up  the  chance  to  buy  another,  etc.) ;  study 
(can  not  play  at  the  same  time)  ;  character,  etc. 

Another  important  question :  Have  we  obtained  any 
of  these  results  without  work  ?     (Not  a  single  one.) 

If  the  amount  of  work  is  small,  the  results  will 
be ?    {Small.) 

If  much  work  is  done ?  (The  results  will  be  cor- 
respondingly great.) 

There  are  few  more  important  lessons  I  can  teach  you 
than  this :  That  nothing  in  this  world  is  obtained  with- 
out giving  its  equivalent ;  and  if  we  choose  one  thing, 
we  must  give  up  something  else.  Now,  let  us  see  some 
things  we  have  learned  of  molecules  : 

They  are  very  small. 

Probably  round. 

Have  space  between  them. 

Do  not  touch. 

(  cohesion   between  like  molecules ; 
Held  together  by  <  adhesion  between  unlike  molecules ; 
(  gravitation  between  all. 

Solids  result  when  these  forces  are  strong. 

Liquids,  when  these  forces  are  weakened. 

Gases,  when  cohesion  and  adhesion  seem  to  disappear. 

That  molecules  can  move  or  vibrate  in  three  ways. 

That  if  they  move  or  stop,  icoi^k  must  make  them. 

That  for  work  we  may  get : 
Change  of  place. 
Change  of  shape. 
Sound — vibrations. 


THE  STUDY  OF  MOLECULES.  149 

Heat  (vibrations  more  rapid). 

Light  (vibrations  still  more  rapid). 

Chemical  energy  (vibrations  most  rapid). 

Electrical  )  .    j.       i       t 

,jr         X-     r  arrangement  of  molecules. 
Magnetic  )  ® 

That  if  we  exchange  work  for  one  of  these,  w^e  can  not 
have  as  much  of  another. 

That  all  molecules  are  in  motion  in  the  space  around 
them,  for  we  know  of  nothing  which  is  not  in  one  or  the 
other  of  the  above  states. 

Which  way  do  you  suppose  they  vibrate  or  swing  ? 
(Back  and  forth,  up  and  down,  or  round  and  round.) 

How  about  the  space  moving  molecules  would  occupy 
compared  with  that  when  still  ?     (More.) 

If  we  increase  the  swing  still  more  ?  (Size  would  in- 
crease.) 

There  were  three  forces  concerned  in  holding  the 
molecules  together,  and  there  is  one  especially  active  in 
overcoming  cohesion,  adhesion,  and  even  seemingly  of 
gravitation,  with  which  we  will  experiment  to-morrow. 

Lesson  18.— The  effects  of  heat. 

Experiment  20. — A  thing  gives  sound  or  is  hot  be- 
cause its  molecules  have  been  made  to  vibrate. 

Heat  a  copper  rod  :  does  it  grow  longer  ? 

Heat  a  brass  ball :  does  it  become  larger  ? 

This  is  called  expansion. 

Do  you  see  why  the  molecules  take  up  more  room  ? 

Suggestions  as  to  apparatus  for  Ex.  21 :  Use  the  dry 
flask  and  its  rubber  cork  with  a  30  cm.  glass  tube  inserted 
for  the  "  air  bulb."  Fill  it  then  with  water  to  test  the 
expansion  of  a  liquid.  The  pulse  glass  is  filled  with  col- 
ored ether  and  vapor  of  ether,  which  quickly  responds  to 
the  heat  of  the  hand. 

Be  sure  the  flask  is  dry  on  the  outside  before  heating, 
or  a  drop  of  cold  water  running  down  on  the  hot  glass 
may  crack  it. 


150  SYSTEMATIC  SCIENCE  TEACHING. 

Experiment  21. — 1.  Make  an  air  bulb  of  your  glass 
flask,  cork,  and  30  cm.  tube.  Dip  the  lower  end  of  the 
tube  in  colored  water  before  putting  in  the  cork,  to  make 
an  index. 

Hold  the  cool  flask  in  your  hands,  and  see  if  the  in- 
closed air  expands.    Set  the  flask  in  cool  water.   (What '() 

2.  Fill  the  flask  full  of  water,  put  in  a  pinch  of  saw- 
dust, and  insert  the  cork  and  tube  tightly.  The  water 
will  rise  in  the  tube.  Mark  the  level  with  a  thread. 
Wipe  dry  on  the  outside,  and,  heating  gently  in  the 
alcohol  flame  or  hot  water,  carefully  observe. 

Does  water  expand  when  heated  ? 

Dip  the  flask  in  cold  water ? 

Why  does  a  "  pulse  glass  "  flow  from  the  bulb  in  your 
hand  ? 

Do  all  the  things  you  have  tried  expand  when  heated  ? 

What  when  cooled  ? 

Prove  this  with  a  thermometer  by  warming  and  cool- 
ing. 

Do  heat  vibrations  seem  to  drive  molecules  apart  ? 

Read  notes  on  how  you  proved  this  with  a  copper 
rod. 

Read  about  the  ball  and  ring.     (See  some  Physics.) 

How  does  a  gas  like  air  behave  ? 

How  a  vapor  like  ether  ? 

How  a  liquid  like  water  ? 

Explain  the  action  of  a  "  thermometer."  (Heat  meas- 
ure.) 

(Both  glass  bulb  and  mercury  are  expanded,  but  while 
the  expanded  bulb  would  hold  more  mercury  and  the 
column  fall,  the  liquid  mercury  expands  so  much  faster 
as  to  make  up  for  all  that  and  more,  hence  rises.  All  this 
is  reversed  when  the  thermometer  is  cooled.) 

Did  any  of  you  observe  the  column  of  water  in  the 
tube  fall  when  you  first  heated  the  flask  ?  It  did,  and  I 
want  you  to  see  and  explain  it. 


THE  STUDY  OF  MOLECULES.  151 

How  about  the  sawdust  f 

Write  these  questions  to  answer  to-morrow  : 

1.  What  state  of  molecules  is  perhaps  represented  by 
swarming  bees  ? 

2.  Why  can  we  weld  hot  iron  and  not  cold  ? 

3.  Why  does  Washington  Monument  nod  each  day  ? 

4.  Why  must  great  iron  tubes  be  free  to  move  at  one 
end? 

5.  Why  do  the  uniting  straps  of  railroad  rails  have 
oblong  holes  ? 

6.  Why  do  iron  gates  stick  in  the  summer  ? 

7.  Why  does  the  blacksmith  heat  wagon  tires  before 
putting  on  ? 

8.  Why  do  the  gas  and  smoke  from  a  fire  rise  ? 

9.  Give  one  of  the  reasons  why  a  full  kettle  of  water 
overflows  when  heated. 

10.  What  is  one  reason  for  the  flow  of  ocean  cur- 
rents ? 

11.  Why  can  warm  air  hold  more  vapor  of  water  than 
cold  air  ? 

Lesson  19. — Who  has  ever  seen  bees  swarming  ? 

Samuel,  you  may  tell  us  how  they  looked.  (Air  filled 
with  a  cloud  of  swiftly  moving  bees.) 

Did  you  see  them  hived  ?  (Yes ;  they  settled  in  a 
bunch  about  as  big  as  a  hat,  and  the  man  shook  them  off 
into  a  hive.) 

Mary  may  tell  me  what  state  of  the  molecules  the  bees 
represent.  (When  heat  sets  them  vibrating  they  are  like 
the  swarm  ;  when  cooled,  like  the  cluster.) 

Thomas,  how  about  welding  iron  ?  (The  cold  mole- 
cules are  not  close  enough  to  cohere,  but  when  set  vibrat- 
ing by  heat,  aided  by  the  hammering,  they  swing  near 
enough  for  cohesion  to  act.) 

Inside  the  Washington  Monument  a  heavy  weight  was 
hung  from  the  top,  its  tip  resting  in  the  smooth  surface 
of  some  dry  sand.     When  kept  from  currents  of  air  it 


152  SYSTEMATIC  SCIENCE  TEACHING. 

was  found  the  weight  traced  a  small  oblong  figure  in  the 
sand  each  day. 

What  made  it  ?  (Kate  :  "  The  sun  shone  first  on  the 
southeast  corner,  and,  expanding  the  stone  more  than  on 
the  shaded  sides,  the  top  was  thrown  a  little  to  the  north- 
west. When  the  sun  was  in  the  south,  the  top  nodded 
north.  As  the  afternoon  came  on  the  southwest  became 
expanded,  and  the  top  was  moved  northeast ;  during  the 
night  it  came  back  into  position  again.") 

The  iron  tubes  ?  (John :  "  Grow  longer  during  the 
heat  of  day  or  summer,  and  shorter  at  night  and  in  win- 
ter ;  and  the  bolts  would  break  if  chance  was  not  given 
for  this  movement.") 

Strap  irons  on  the  railroad?  (Jane:  "The  rails 
lengthen  and  shorten,  and  would  break  the  bolts  or 
straps  if  a  chance  to  slip  was  not  given.") 

Henry,  does  this  have  anything  to  do  with  the  rails 
having  a  space  at  one  or  both  ends  ?  (Same  reason  ;  the 
track  would  bend  up  or  to  one  side  in  a  hot  day,  if  space 
to  expand  was  not  provided.) 

Who  has  observed  about  iron  gates  ?  (Susie  :  "  Ours 
sticks  so  that  I  have  had  to  climb  the  fence.") 

Well  done  for  a  girl ! 

Why  did  it  stick  ?  (The  molecules  of  iron  must  have 
been  flying  about  on  that  hot  day,  and  took  so  much 
room  that  the  gate  was  too  big.) 

Alice :  "  Our  wooden  gate  sticks  when  it  rains.  Is  it 
for  the  same  reason  ? "  (Samuel :  "  No ;  it  swells.'''') 
(Henry :  "  I  think  adhesion  makes  the  water  get  in  be- 
tween the  cracks  of  the  wood.") 

That  is  well  said,  Henry. 

Who  has  ever  seen  a  wagon  tire  set  ?  (Robert :  "  The 
smith  put  the  four  tires  together  on  the  ground,  piled 
sticks  and  corncobs  around  the  circle,  and  set  them  on 
fire.  The  wheel  was  laid  down  on  a  wooden  frame,  and 
when  the  tires  were  real  hot  two  men  took  one  with 


THE  STUDY  OF  MOLECULES.  153 

tonj^s  and  slipped  it  on  the  wheel.  The  wood  of  the 
wheel  began  to  burn,  so  they  quickly  slipped  the  wheel 
on  a  pin  over  a  trough  of  water  and  whirled  it  round  a 
few  times.  Then  the  other  wheels  were  done  in  the  same 
way,  and  the  smith  said  they  were  '  shrunk  on  so  tight 
they  would  never  come  off.'  ") 

Well  told  ;  but  now  explain  why.  (Ann :  "  Tlie  cobs 
made  the  molecules  separate,  and  the  iron  hoop  got  so 
large  that  it  slipped  on  easily,  and  when  cooled  in  the 
water  the  molecules  came  nearer  to  each  other  again  and 
squeezed  the  wheel  tightly.") 

Why  do  the  smoke  and  gas  from  a  fire  rise  ?  (Paul : 
"You  told  us  in  the  pebble  lessons  that  warm  air  is 
lighter,  and  I  think  the  reason  is  that  it  is  like  a  swarm 
of  bees.") 

John  asks,  "  But  why  does  it  risei  " 

A  good  question,  John,  and  one  I  think  the  class  can 
understand  and  answer  too.  We  will  all  try  some  ex- 
periments to  think  over  for  to-morrow's  answer  to  this 
question. 

Experiment  22. — Why  a  cork  floats  and  hot  air  rises. 

Fill  your  graduates  to  the  30  c.  c.  mark. 

Drop  in  a  large  marble  or  piece  of  stone.  Read  gradu- 
ate and  record. 

Drop  in  a  dry  cork,  and  read  how  much  the  water  rises. 

Push  the  cork  below  the  surface  by  a  wire  or  pencil 
point,  and  read  again. 

Take  away  the  wire  or  pencil.  What  does  the  cork 
do  ?    The  water  ? 

A  balloon  in  the  air  would  be  like  this  cork  in  water. 

Do  these  experiments  help  you  in  answering  the 
questions  ? 

Lesson  20. — Now  for  our  questions.  Let  us  put  the 
results  of  yesterday's  experiments  on  the  board. 

Samuel :  "  Graduate  at  30  c.  c.  -f  marble  =  34  c.  c.  =  rise 
of  4c.c." 


154  SYSTEMATIC  SCIENCE  TEACHING. 

Kate  :  "  Graduate  at  34  c.  c.  +  cork  =  36  c.  c.  =  rise  of 
2c.c." 

Thomas :  "  Graduate  at  36  c.  c.  +  cork  all  under  =  42 
c.  c.  =  rise  of  6  c.  c." 

Paul:  "Removed  pressure  on  cork."  (Cork  rose  and 
water  fell  to  37  c.  c.) 

Who  will  tell  me  what  this  means  ?    (Probably  none.) 

Has  water  weight  ?    (Yes.) 

Has  cork  weight  ?    (Yes.) 

One  c.  c.  of  water  weighs ?    (1  gramme.) 

When  the  weight  of  the  cork  rests  on  the  water,  what 
happens  ?    (Water  rises.) 

See  this  scale.  I  put  5  grammes  in  this  pan,  and  it 
falls.  How  much  must  I  put  in  the  other  pan  to  bal- 
ance it  ?     (An  equal  weight.) 

Now,  the  water  is  a  wonderfully  exact  scale  and 
weight  combined. 

In  every  case  yesterday,  as  the  cork  or  stone  went 
down,  the  water ?    (Rose.) 

As  the  cork  rose  above  the  surface,  the  water ? 

(Fell.) 

As  the  cork  pressed  down  upon  the  water  the  water 
rose  till  it  balanced  the  cork.  What  weight  of  water 
would  do  that  ?     (Equal  to  the  cork.) 

How  can  I  get  the  cork  to  lift  more  than  its  weight  of 
water  ?    (By  pressing  on  it.) 

Yes,  the  cork  raised  2  grammes  of  water,  and  by  push- 
ing I  can  make  it  raise  8.  Now,  if  2  grammes  of  water 
can  hold  the  cork  still,  what  will  8  grammes  pushing  on 
it  do  ?    (Make  it  rise.) 

How  high  ?    (Till  6  c.  c.  have  risen  out  of  the  water.) 

Then  a  submerged  thing  that  is  lighter  than  the  air 

or  liquid  it  is  in  rises  because ?    (It  is  pushed  up 

harder  than  it  can  press  down.) 

There  is  much  more  I  should  like  to  teach  you  about 
this,  but  it  will  come  in  better  at  another  time  (Step 


THE  STUDY  OF  MOLECULES.  155 

XXXVII,  etc.).  Let  us  think  first  of  the  water  and  saw- 
dust in  Ex.  21.  Before  heating,  the  sawdust  in  the 
water  was  still.  You  heated  the  bottom  of  the  flask 
and  the  water  next  to  it  first.  The  heat  made  this  wa- 
ter  ?     (Expand.) 

Was  the  expanded  water  lighter  or  heavier  than  the 
cool  layers  above  it  ?    (Lighter.) 

Now,  do  you  see  how  like  the  submerged  cork  it  was  ? 
The  greater  weight  of  the  water  above  obliged  the  heated 
water  to ?     (Rise.) 

And  as  it  rose  the  cold  water ?     (Fell.) 

Why  did  I  have  you  drop  sawdust  in  ?  (So  that  we 
could  see  this  rising  and  falling.) 

Now  for  our  heated  air.  The  air  next  the  warm 
water  (see  §  16,  Step  XV)  became  heated.  This  caused 
the  molecules  to  vibrate  and  take  up  more  room,  and  we 
say  the  air ?    (Expands.) 

Above  was  the  cold  air,  so  what  had  to  happen  ? 
(Warm  air  rose,  and  the  cold  air  flowed  in.) 

What  did  we  call  these  inflowing  currents  ?    (Winds.) 

Air  mixed  with  vapor  is  also  light  (see  Barometer, 
Step  XV).    What  will  it  do  ?    (Rise.) 

The  heated  air  from  fires,  etc. ?     (Rises.) 

Is  this  point  clear  ?    If  so,  we  will  go  on. 

Why  does  a  kettle  full  of  cold  water  overflow  when 
heated  ?    (Water  expands.) 

What  is  one  reason  for  the  flow  of  ocean  currents 
(show  map  of  Gulf  Stream,  etc.)  ?  (Same  as  water  in 
flask.  The  oceans  under  the  continual  heat  of  the  tropics 
become  heated  on  top,  and  are  not  able  to  balance  the 
cold  waters  on  either  side,  which,  pressing  under,  compel 
the  warm  water  to  flow  off.) 

Why  can  heated  air  hold  more  vapor  than  cooled  air 
(see  §  16,  Step  XV)  ?  (Is  like  the  unsqueezed  sponge, 
with  larger  spaces  between  the  molecules  for  the  vapor 
to  get  into.) 


156  SYSTEMATIC  SCIENCE  TEACHING. 

So  much  for  the  way  heat  overcomes  cohesion,  etc., 
and  by  separating  the  molecules  makes  solids,  liquids, 
and  gases  expand.  Let  us  to-day  see  what  happens  when 
we  heat  a  solid  still  more. 

Experiment  23. — Heat  a  piece  of  solid  ice  in  a  spoon. 
What  ? 

Heat  the  liquid  water  still  more.    What  ? 

Light  a  bit  of  candle,  and  write  the  history  of  what 
happens  as  the  solid  tallow  melts  to  liquid,  etc. 

Lesson  21.— A  solid  when  heated  first  ?    (Expands.) 

If  heated  still  more,  till  the  molecules  vibrate  very 
fast  and  far  ?    (Melts.) 

Still  more  vibration  ?    (Vaporizes.) 

What  forces  had  the  heat  to  overcome  in  expanding  a 
solid  ?    (Cohesion  and  gravitation.) 

In  melting  ice  ?    (Cohesion.) 

In  vaporizing  water  ?  (Cohesion — of  water ;  adhesion 
— to  dish  ;  and  gravitation — push  away  the  air.) 

How  can  I  stop  these  vibrations  and  get  back  my  ice 
again  ?    (Cooling.) 

What  is  "  cold  "  ?    (Simply  loss  of  motion  of  heat.) 

If,  then,  I  bring  something  whose  molecules  are  mov- 
ing but  little,  near  or  in  contact  with  another  object 
whose  molecules  are  in  rapid  motion,  what  will  happen  ? 
(The  molecules  of  the  hot  thing  will  give  of  their  motion 
to  the  cool  thing  till  both  are  equal.) 

The  old  law  of  loss  and  gain !  To  heat  one  thing,  an- 
other must ?    (Cool.) 

To  cool  an  object ?    (Another  must  warm.) 

Now,  about  the  candle  ?  Jane,  you  may  read  your 
notes.  C I  lit  the  candle.  The  heat  melted  the  solid  tal- 
low into  a  liquid,  and  this  rose  up  the  wick,  and,  heated 
still  more,  became  a  gas,  which  burned  with  a  flame.") 

I  can  not  explain  all  this  to  you  now,  but  some  day 
you  will  learn  how  heat  vibrations  first  expand,  then 
melt,  then  vaporize,  and,  last  of  all,  tear  the  little  mole- 


THE  STUDY  OF  MOLECULES.  157 

cules  into  the  still  smaller  atoms  we  have  talked  of.  No 
"cooling"  can  then  ever  give  us  back  our  molecule 
again,  any  more  than  we  can  get  back  tallow  or  wax  by 
cooling  the  gas  and  vapor  that  rise  from  the  candle. 

But  the  heat  of  the  flame  did  not  touch  the  ice  or 
water,  and  to  show  how  its  motion  was  passed  by  the 
spoon  from  flame  to  ice,  let  us  try  some  experiments. 

Experiment  24.— To  explain  how  the  heat  of  the  flame 
could  do  this  through  the  spoon,  place  five  or  more  equal- 
sized  marbles  in  the  groove  of  a  level  piece  of  flooring, 
and  when  all  touch,  gently  tap  one  end  of  the  row  and 
note  what  happens.  Do  this  five  times.  Write  what  you 
saw.  How  does  this  help  you  to  understand  the  way  the 
heat  got  through  the  spoon,  or  the  sound  from  a  bell  to 
your  ear  ? 

Experiment  25. — Take  a  long  slate  pencil,  and  rods  as 
nearly  as  possible  of  equal  size  and  length,  of  iron,  cop- 
per, and  wood.  Place  pieces  of  wax  or  tallow  the  size  of 
a  No.  5  shot  equally  distant  from  one  end  of  each.  Now, 
in  turn,  hold  one  cm.  of  this  end  of  each  in  the  same  part 
of  a  lamp  or  gas  flame,  and  record  the  time  it  takes  to 
melt  the  wax  or  tallow,  up  to  three  minutes.  Do  all 
things  carry  heat  equally  fast  ?  "W  hich  the  poorest  of 
all? 

Lesson  22. — What  happened  when  you  tapped  the 
end  of  the  row  of  marbles  ?  (All  stayed  still  except  the 
last  one,  which  was  thrown  off.) 

Why  was  this  ?  (The  pencil  struck  the  first  one  a 
blow,  which  it  passed  to  the  next,  that  one  to  the  next, 
and  so  on  till  the  last  one,  having  nothing  to  hold  it 
back,  flew  off.) 

How  does  this  illustrate  the  passage  of  the  heat  vibra- 
tions through  the  spoon  ?  (The  blows  of  the  flame  were 
given  up  to  the  spoon ;  then  the  molecules  of  the  spoon 
passed  them  along  till  they  in  turn  gave  them  up  to  the 
ice,  and  the  ice  molecules  were  set  swinging  so  violently 


158  SYSTEMATIC  SCIENCE  TEACHING. 

as  to  get  beyond  the  control  of  cohesion,  and,  slipping 
apart,  became  liquid  water.) 

How  were  the  vibrations  of  the  bell  brought  to  the 
ear  ?  (The  bell  set  the  molecules  of  air  next  it  to  swing- 
ing, these  passed  the  blow  to  those  next,  and  so  on  till 
the  last  ones  struck  the  ear,  and  we  "  heard.") 

James  may  read  his  notes  about  the  rods.  ("  Took  an 
iron  nail,  copper  rod,  slate  pencil,  and  wood  skewer. 
Got  the  ends  even,  and  made  a  mark  across  them  all  6 
cm.  from  the  even  ends.  On  each  mark  laid  a  small 
piece  of  wax,  and  kept  time  while  I  held  the  ends  suc- 
cessively in  the  flame.  Iron  nail  carried  heat,  and  wax 
began  to  melt  in  20  seconds.  Copper  rod  carried  heat, 
and  wax  began  to  melt  in  15  seconds.  Slate  pencil  car- 
ried heat,  and  wax  began  to  melt  in  90  seconds.  Wood 
began  to  burn,  and  burned  to  the  wax  in  165  seconds.") 

Very  good. 

Do  all  things  carry  heat  equally  well  ?    (No.) 

Which  the  best  ?    (Metals.) 

Which  the  poorest  ?     (Wood.) 

What  do  the  poorest  conductors  do  ?    (Take  fire.) 

Which  seem  to  "pass  the  knock  along"  the  most 
easily  ?    (Metals.) 

Why  do  wood  and  other  things  that  burn  conduct 
the  vibrations  so  poorly  ?  (Have  holes  and  breaks  be- 
tween the  molecules,  which  the  vibrations  can  not 
cross.) 

Should  you  think  liquids  would  conduct  heat  well  ? 
(No ;  the  spaces  between  the  molecules  are  large.) 

This  is  truly  the  case,  and  we  find  it  very  hard  to  heat 
liquids  from  the  top  downward.  When  heated  at  the 
bottom  what  happens  ?  (Rising  and  falling  currents  are 
set  up,  as  in  the  flask.) 

How  will  air  and  gases  heat  ?  (Poorest  of  all,  as  the 
molecules  are  so  widely  separated.) 

How   our  study  of    molecules  helps   us  to  explain 


THE  STUDY  OF  MOLECULES.  159 

thinj^s !    Best  of  all,  it  will  be  the  key  to  very  much  that 
is  to  follow. 

There  is  still  another  question  about  them.  When 
they  separate  through  heat  or  draw  together  through  its 
loss,  is  it  with  much  or  little  force  f  I  will  give  you 
some  things  to  think  over  for  to-morrow. 

1.  Remember  Washington's  Monument  nods. 

2.  Remember  how  huge  iron  tubes  (bridges  like  that 
over  the  St.  Lawrence  at  Montreal,  or  across  the  Straits 
of  Menai)  have  the  ends  on  rollers,  and  at  times  move 
several  feet  in  a  day. 

3.  Remember  the  oval  holes  in  railroad  rails. 

4.  Brooklyn  Bridge  is  said  to  rise  and  fall  at  the  cen- 
ter several  feet  each  day. 

5.  A  building  in  Paris  had  a  very  heavy  roof,  and  the 
walls  began  to  spread.  It  was  brought  into  place  by 
running  huge  iron  rods  through  from  one  side  to  the 
other.  Each  had  a  thread  and  nut  on  one  end,  and  every 
other  one  had  a  row  of  gas  jets  under  it.  How  did  the 
men  manage  ? 

Lesson  23.— Samuel,  what  makes  the  Brooklyn  Bridge 
rise  and  fall  at  the  center  ?  ("  The  heat  of  day  expands 
the  cables,  and  the  center  drops  ;  during  the  night  the 
cables  contract,  and  the  center  rises.") 

Jane,  is  it  much  work  to  raise  and  lower  this  bridge  ? 
("Much.") 

John  may  tell  me  about  the  Paris  building.  ("  The  gas 
was  turned  on,  and  expanded  the  alternate  rods,  which 
were  screwed  up  tight  while  hot,  and  on  cooling  con- 
tracted and  drew  the  walls  together  a  little.  The  other 
set  of  rods  thus  became  loose,  and  were  screwed  up. 
This  was  repeated  as  often  as  required.") 

Was  much  power  shown  ?     ("  Very  much.") 

Robert  may  tell  me  what  he  thinks  of  the  monument. 
(The  expansive  force  to  lift  half  that  column  of  stone 
must  be  immense.) 


160  SYSTEMATIC  SCIENCE  TEACHING. 

Mary,  tell  me  about  the  bridge  ends.  ("  Great  power 
needed  to  move  such  masses  of  iron.") 

James  may  speak  of  the  rails.  ("  If  chance  were  not 
given  for  the  ends  to  move,  the  rails  would  warp  up  or 
sidewise,  showing  tremendous  power.") 

There  seems  to  be  no  doubt  but  this  motion  of  the 
molecules  is  made  with  enormous  force — a  force  able  to 
do  almost  anything,  and  wholly  beyond  our  power  to 
stop.    Now  comes  our  last  experiment. 

Experiment  26. — Take  a  cold  glass  marble  and  sud- 
denly heat  it  in  a  hot  flame  or  fire.  Record  and  explain 
what  happens.  Now  drop  a  marble  whose  molecules  are 
in  rapid  vibration  in  cold  water.     Record  and  explain. 

Who  can  picture  the  molecules  of  the  hot  marble  to 
me  ?    (A  mass  of  violently  moving  parts.) 

Is  glass  a  good  conductor  of  heat  ?  (No ;  for  we  held 
8  cm.  bits  in  a  flame  till  the  middle  softened  enough  to 
bend.) 

Suppose  this  violently  moving  mass,  in  its  expanded 
condition,  suddenly  has  the  outside  cooled  by  dropping 
in  water?  (The  outside  would  suddenly  contract  over 
the  expanded  interior,  and,  being  too  small  to  fit  it, 
would  have  to  break.) 

Why  would  not  an  iron  ball  do  the  same  ?  (One  rea- 
son would  be  that  such  a  good  conductor  of  heat  vibra- 
tions could  not  be  suddenly  enough  stopped.) 

Who  will  explain  the  chipping  off  of  a  suddenly 
heated  marble  ?  (The  outside  tried  to  expand  before  the 
cool  inside  could  follow,  and  they  had  to  separate.) 

Why  do  lamp  chimneys  often  break  when  placed  over 
a  very  hot  flame  ?     (Inside  expands  too  quickly.) 

Why  break  from  a  draught  or  spatter  of  water  ? 
(Outside  contracts  over  the  hot  inside.) 

Why  does  hard  coal  snap  so  when  put  on  a  hot  fire  ? 
(Same  as  cold  marble.) 

Indians  used  to  cook  in  pails  of  birch  bark  by  heating 


THE  STUDY  OF  MOLECULES.  IGl 

stones  and  dropping"  them  in  among  the  meat.  How  did 
it  affect  the  stones  ?     (Cracked.) 

This  brings  us  pretty  close  to  the  answer  of  the  ques- 
tion we  started  with. 

What  is  another  way  (besides  roots  and  frost)  sharp 
stones  might  be  made  ? 

How  many  have  enjoyed  asking  Nature  questions  ? 

Your  gain  in  knowledge  has  been  far  beyond  what 
you  can  now  realize.  But,  interesting  and  helpful  as  it 
has  been,  we  shall  all  enjoy  a  change. 

Review. — But  little  is  needed,  as  this  work  will  all 
come  up  again  in  new  relations,  and  the  work  being  done 
by  the  pupil  will  be  a  part  of  his  personal  experience^ 
and  not  easily  forgotten. 

Should  time  permit,  the  following  will  be  profitable : 

1.  Each  one  tell  me  something  he  has  particularly 
noticed  in  these  lessons.  (Go  round  the  class  as  hands 
are  raised,  but  see  that  the  dull  and  less  interested  ones 
get  a  first  chance  and  a  frequent  one.  The  bright  pupils 
can  afford  to  keep  still.  No  one  must  repeat  what  an- 
other has  told,  but  may  always  add  to  or  modify  if  he 
deems  it  desirable.     See  reviews  in  previous  lessons.) 

2.  Has  any  one  a  question  to  ask  or  subject  he  wishes 
more  light  on  ?  (Let  them  understand  that  good  ques- 
tions show  thought  and  care,  and  are  much  to  the  credit 
of  the  asker.) 

If  marking  must  be  done,  let  it  include  four  things  : 
Character  of  work  in  experimenting. 
Concise  and  yet  full  notes. 
Neatness  in  notes  and  in  experimenting. 
General  grasp  of  the  subject. 

Material  and  apparatus  should  now  be  put  away,  clean 
and  ready  for  the  next  class. 

Next  step  along  this  line,  XXXVI— Crystals. 


12 


STEP  XXXII.— MAX. 

The  object  of  this  step  is  to  show  how  man,  the  high- 
est animal,  adapts  himself  to  the  varied  conditions  of  his 
environment.  How  "want"  has  been  "the  mother  of 
invention."  This  will  continue  the  idea  of  Animals  in 
Winter  Quarters  (Step  XXIX),  and  that  of  Plant  Rela- 
tionship (Step  XXVIII).  To  aid  in  other  ways,  the  races 
and  distribution  of  man  are  observed,  and  the  work  so 
arrangfed  as  to  present  to  the  child  general  ideas  regard- 
ing the  evolution  of  modern  civilized  life. 

The  time  of  the  year  will  fall  in  late  spring,  and  about 
forty  lessons  of  half  an  hour  each  will  be  sufficient.  In 
order  to  bring  so  ambitious  a  subject  within  such  limits,  it 
must  be  clearly  kept  in  mind  that  this  stage  of  the  work 
is  suggestive  rather  than  exhaustive,  and  each  topic  must 
be  briefly  and  energetically  treated  and  then  promptly 
dropped  for  the  next.  Presented  thus,  the  pupil  has  his 
eyes  opened  to  new  relations  of  things,  and  is  left  with 
that  awakened  interest  which  desires  to  know  more. 

Equipment. — A  good  globe  and  a  large  map  of  the 
world,  with  books  to  which  the  pupils  can  have  access 
for  information.  Pictures  of  man  in  the  various  sur- 
roundings of  differing  climate ;  specimens  and  models  of 
dress,  food,  manufactures,  dwellings,  etc.,  will  also  help, 
and  may  little  by  little  form  a  very  interesting  collection 
for  the  school. 

The  map  must  be  hung  low  enough  so  that  pupils  can 
reach  all  parts  of  it.  A  good  way  is  to  have  a  large  out- 
line made  on  a  low,  soft  pine  blackboard.  Color  each 
162 


MAN.  163 

portion  of  the  land  with  that  of  the  race  of  man  found 
there  (red,  black,  yellow,  brown,  and  white),  as  given  in 
some  physical  geography.  These  colors  will  stand  for  the 
race,  and  the  principal  divisions  of  land  can  be  named 
in  small  lettering  on  the  margin.  On  this,  as  the  work 
proceeds,  can  be  affixed,  by  small  tacks  or  short,  strong 
pins,  the  models,  drawings,  pictures,  or  samples  of  food, 
etc.,  each  in  its  proper  locality.  This  map  should  be 
easily  accessible  to  the  pupils  during  school  hours,  and 
will  grow  in  interest  as  the  work  proceeds,  presenting  a 
bird's-eye  view  of  the  whole  at  the  end. 

Preparation  of  the  Teacher.— Go  through  the  lessons 
carefully,  using  such  books  of  reference  as  your  pupils 
will  have,  and  in  the  spirit  of  a  child  travel  the  road  you 
are  to  lead  them  over,  that  all  stumbling  may  be  warned 
against,  and  hesitation  on  your  part  be  avoided. 

The  most  helpful  books  at  my  command  have  been 
Tylor's  Anthropology,  Tylor's  Early  History  of  Man- 
kind ;  Wood's  Natural  History — Man,  Vols.  I  and  II ; 
Riverside  Natural  History,  Vol.  V ;  Drummond's  Ascent 
of  Man. 

Arrange  for  each  pupil  to  have  a  notebook  about  eight 
inches  wide. 

The  Lessons  Introduced.— What  traveling  animal  was 
omitted  from  our  study  of  migration  and  hibernation  ? 
(Man.) 

In  observing  the  relationships  of  plants,  what  impor- 
tant one  was  in  great  measure  left  out  ?     (That  to  man.) 

A  famous  poet  has  said,  "  The  proper  study  of  man- 
kind is  man,"  and  it  is  to  consider  our  own  most  impor- 
tant position  in  the  world  of  Nature  that  we  shall  pursue 
this  step. 

How  many  zones  (or  climates)  do  maps  show?  (Frigid, 
temperate,  torrid.)  * 

*  Teacher  explain  each  of  these  terms. 


164  SYSTEMATIC  SCIENCE  TEACHING. 

In  which  season  of  the  year  can  our  native  animals 
and  birds  live  the  most  easily  ?     (Summer.) 

Which  of  the  earth's  zones  is  most  like  summer  ? 
(Torrid.) 

Men  who  have  studied  about  the  matter  find  that  man 
has  not  always  been  as  comfortable  nor  had  so  many 
things  to  do  with  as  we,  but  that  there  was  a  time  when 
he  was  wild  and  savage,  living  on  fruits  and  roots,  and 
with  perhaps  not  even  a  shelter  at  night. 

In  which  climate  could  such  people  live  ?  (Tropi- 
cal.) 

Now,  in  our  study  of  how  mankind  gradually  im- 
proved on  this  wild  state  of  the  tropics,  and  became  what 
we  see  about  us  to-day,  we  will  follow  this  plan. 

1.  Take  color  as  a  convenient  method  of  classifying 
the  differing  races  of  man  (as  on  this  blackboard  map  of 
the  world). 

2.  Starting  with  the  wild  man  of  the  tropics,  we  will 
consider  what  he  had,  and  then,  as  he  migrated  to  other 
climates,  how  he  adapted  his  life  to  the  new  surround- 
ings. 

3.  That  we  may  more  clearly  trace  the  steps  of  prog- 
ress, we  will  take  the  following  topics,  each  by  itself: 
Food,  weapons,  fire,  utensils,  conveyance,  buildings,  lan- 
guage, permanent  expression. 

Before  taking  up  these  topics,  one  question  needs 
thought.  Why  should  tropical  man  migrate  ?  With  fruits 
and  roots  to  live  upon,  and  so  little  need  of  clothing  and 
shelter,  why  go  to  other  places  where  life  is  frequently 
more  difficult  to  maintain  ?  Why  do  animals  migrate  ? 
Why  do  our  native  birds  disappear  before  the  English 
sparrow  ?  Why  are  the  Indians  not  found  in  the  eastern 
United  States  ?  Why  did  the  white  man  come  to  Amer- 
ica ?  Why  do  trappers  brave  the  dangers  of  Hudson's 
Bay,  and  whalers  the  icy  seas  of  the  north  ?  Why  do 
bees  swarm  ? 


MAN.  165 

The  Lessons. 

Before  each  topic  let  the  teacher  instruct  the  pupils 
where  to  look  for  such  information  as  shall  supplement 
that  which  their  previous  reading,  geography,  and  his- 
tory has  supplied. 

The  study  of  such  charts  as  Guyot  gives  in  his  Phys- 
ical Geography,  or  the  pictures  in  Frye's  Complete  Geog- 
raphy, will  be  very  helpful.  Accustom  them  to  take 
brief  notes  of  what  they  find,  and  where. 

Now,  with  a  large  map  before  the  class,  and  notebooks 
in  hand  to  briefly  record  what  is  said,  all  is  ready. 

Food. 

Let  us  rule  our  notebooks  into  three  portions,  the  left- 
hand  and  middle  ones  twice  the  width  of  the  right-hand 
one.  Head  the  left-hand  column  "Food,"  the  middle 
column  "People  and  Place,"  the  right-hand  column 
"Authority." 

Wild  people  are  much  like  animals,  roving  about  with 
no  real  home.  Who  has  found  out  about  such  a  people  ? 
(Indians  of  Brazil.)  Write  that  in  the  middle  column. 
Where  did  you  find  the  references  ?     (T.,  206  to  214.)  * 

Place  that  in  the  right-hand  column  under  "Au- 
thority." 

What  does  Mr.  Tylor  say  they  eat?  (Wild  fruits, 
roots,  reptiles,  etc.) 

Write  these  in  the  left-hand  column. 

What  seems  the  first  advance  in  this  matter  over  the 
wild  beasts  ?  (Tool  making,  such  as  hooks  and  nets  to 
catch  fish,  and  traps  for  animals.) 

*  In  what  follows,  "T."  stands  for  Tylor's  Anthropology  j- 
"  T.  E."  for  Tylor's  Early  History  of  Mankind ;  "  N.  H."  for 
Riverside  Natural  History,  Vol.  V*;  "  W.,  I "  (or  II)  for  Wood's 
Natural  History  of  Man,  Vol.  I  (or  Vol.  II). 


166 


SYSTEMATIC  SCIENCE  TEACHING. 


Can  you  name  a  people  living  where  such  food  is  apt 
to  fail  ?    (Indians  of  North  America,  N.  H.,  148  and  155.) 

Your  authority  ?     (Hiawatha's  fasting.) 

How  did  they  provide  ?     (Raised  corn,  etc.) 

This  would  be  the  beginning  of  what  important  in- 
dustry ?    (Agriculture.) 

Have  you  found  any  people  which  differ  from  either 
of  these  given  ?  (Tunguz  (pronounced  Tungooz)  of  north- 
eastern Asia,  T.,  219,  220.) 

These  live  how  ?  (By  the  flesh  and  milk  of  domesti- 
cated animals.) 

What  advance  can  be  made  on  either  of  these  ?  (The 
union  of  agriculture  and  herding,  as  in  Genesis  xxvi,  12- 
14,  and  the  tribes  of  northern  Europe,  T.,  220.) 

How  is  food  obtained  to-day  ?  (Through  the  medium 
of  commerce,  whereby  each  can  have  the  produce  of  all 
the  earth,  and  where  the  want  of  one  country  is  supplied 
by  the  surplus  of  others.) 

The  pupils'  notebooks  should  now  present  an  appear- 
ance somewhat  like  the  following : 


Food. 

Wild  fruits,  roots, 
reptiles,  eggs,  hon- 
ey, game,  aiid  fish. 

Add  cultivated  corn, 
etc. 

Flesh  and  milk  of 
domestic  animals. 

Agriculture  and 
herds. 

Commerce.  "Want 
of  one  place  sup- 
plied by  surplus  of 
others. 


People  and  Place. 

Red  Indians  of  Bra- 
zil, South  Amer- 
ica. 

Red  Indians  of 
North  America. 

Tunguz  of  north- 
eastern Asia. 

Isaac  and  patriarchs. 
Old  tribes  of 
northern  Europe. 

All  nations  and 
tribes. 


Authority. 
Tylor,  206-214. 


Longfellow's  Hiawa- 
tha; N.H.,  155. 
Tylor,  219,  220;  N. 

Bible,  Genesis  xxvi, 
12-14;  T.,  220. 


MAN.  167 

It  will  at  once  occur  to  the  teacher  that  the  above 
is  very  brief  and  incomplete ;  but  it  introduces  the 
matter  to  the  child's  notice,  and  if  the  lessons  are  to  be 
kept  fresh  and  bright  much  time  can  not  be  given  to 
each  point.  Moreover,  the  subject  of  food  will  be  con- 
tinually appearing  incident  to  the  consideration  of  other 
topics ;  hence  would  promptly  pass  to  the  next  subject. 
Again,  in  advance,  instruct  the  class  what  to  read  about, 
and  where. 

Tools  and  Weapons. 

In  getting  food  we  have  already  observed  the  need 
man  had  for  various  aids.  The  way  these  grew  out  of 
his  needs  is  one  of  the  most  interesting  cnapters  of  hu- 
man history. 

We  do  not  know  of  any  race  of  men  who  are  in  the 
first  stages  of  tool  making,  and  so  let  us  try  to  imagine 
what  they  could  have  found  to  use.  (Sticks— round  or 
sharp — stones,  thorns.) 

The  first  could  be  used  to ?     (Strike,  push,   or 

throw.) 

The  second  could  be  used  to ?    (Throw  or  pound.) 

The  third  (sharp  stones)  to ?     (Cut,  hack,  scrape, 

saw,  rasp.) 

With  the  fourth  (thorn,  bone  splinter,  flake,  etc.)  ? 
(Make  holes  to  sew,  etc.) 

Having  noted  these  in  your  books,  let  us  trace  how 
the  inventiveness  of  man  has  developed  the  numerous 
tools  of  to-day. 

The  Stick  to  Strike. — Have  you  found  any  peoples 
using  it  ?    (Fiji  Islanders ;  N.  H.',  67,  68,  and  T.,  184.) 

Yes,  and  all  peoples  use  the  stick  to  kill  a  snake. 

What  improvement  has  there  been  ?  (Carved,  orna- 
mented, and  set  with  sharp  teeth  and  bits  of  bone  or 
teeth  by  the  Fiji  Islanders,  or  set  with  sharp  flakes  of 
stone  by  the  American  Indians.) 


168  SYSTEMATIC  SCIENCE  TEACHING. 

These  made  terrible  weapons  to  fight  with. 

If  the  branch  or  club  were  flattened  to  an  edg^e  it  would 

form ?    (Wooden  sword ;  of  Nootka  Sound  Indians^ 

N.  H.,  138.) 

What  peaceful  use  would  such  broad,  flat  blades  serve 
in  traveling  on  water  ?  (Paddles ;  of  New  Zealanders, 
W.  II,  174.) 

If  one  pointed  tooth  or  stone  were  set  in  the  club  it 
would  make ?    (Pick  ;  Eskimos,  N.  H.,  122 ;  T.,  187.) 

If  this  pick  were  flattened  to  an  edge  parallel  to  the 
handle ?     (Axe ;  T.,  189,  190.) 

With  the  handle  shortened  and  blade  of  metal  length- 
ened  ?    (Sword.) 

What  peaceful  instruments  seem  to  have  grown  out 
of  this  ?     (Sickle  and  scythe  ;  T.,  190.) 

Returning  to  the  pick  and  flattening  the  edge  at  right 

angles  to  the  handle,  it  would  be ?     (Adze ;  of  the 

Polynesians,  T.,  189.) 

For  what  use  would  these  serve  in  tribes  which  culti- 
vated crops  ?  (Hoe ;  of  North  American  Indians,  N.  H., 
165 ;  T.,  216.) 

The  pick  made  heavier  and  dragged  over  the  ground 
it  was  desired  to  loosen  became  the ?  (Plow ;  of  Swe- 
den, and  used  in  the  Azores  to-day,  T.,  217.) 

Stick  to  Push  with. — Finding  that  it  was  an  advan- 
tage to  have  the  end  pointed,  man  first  did  it  by ? 

(Burning;  T.,  194.) 

What  was  the  next  improvement  ?  (Tipped  with 
sharp  bit  of  bone  or  ivory,  by  Eskimos,  W.,  II,  706 ; 
stone,  by  North  American  Indians,  W.,  II,  651 ;  or  metal 
of  more  recent  date,  T.,  189.) 

How  would  such  a  spear  aid  in  the  search  for  roots  ? 
(To  dig ;  Digger  Indians,  N.  H.,  177.) 

Made  broader,  and  of  metal,  this  would  become  the 
modern ?     (Spade  ;  T.,  216.) 

If  the  stick  had  several  points  (as  the  Australian  fish 


MAN.  169 

spear,  N.  H.,  32)    it  would   naturally  lead  to   the ? 

(Fork,  still  used  in  the  Azores.) 

Shorter  and  smaller,  this  would  become  the  table 
fork. 

The  stick  to  throw  is  used  by  all  tribes  (as  Kaffir,  W., 
1, 108). 

Curved  and  flat,  it  becomes  the ?    (Boomerang  of 

Australia  ;  N.  H.,  33.) 

When  long  and  pointed,  it  became (The  assagai 

of  South  Africa;  W.,  I,  103.) 

Lighter  spears  would  form  the ?    (Arrow.) 

Where  the  bow  originated  is  unknown  (T.,  195). 

The  smooth  stone  would  first  be  used  for  a  missile,  as 
when  any  one  "  throws  stones "  (W.,  II,  41).  This  use 
early  gave  rise  to  the  sling,  which  gave  the  stone  a  higher 
speed  (T.,  193,  194).  Held  in  the  hand,  the  stone  formed 
the  first  hammer  (T.,  184,  W.  I.,  98). 

What  improvement  would  relate  it  to  the  axe  ? 
(Adding  a  handle.) 

What  need  arose  as  man  began  to  use  grain  for  food  ? 
(To  crush  the  seeds  for  bread  making.) 

What  was  the  earliest  mill  ?  (Mortar  and  pestle  of 
stone,  as  of  California  Indians ;  N.  H.,  212,  and  T.,  200.) 

Improved,  this  became  the  "  metate  "  of  the  Mexicans 
(T.,  201 ;  N.  H.,  195).  Just  how  this  crushing  by  a  roller 
changed  to  the  crushing  by  one  stone  revolving  on  an- 
other is  not  known,  but  such  hand  mills  have  been  used 
from  the  earliest  historic  time  to  the  present  (is  now 
used  in  the  Azores),  and  was  the  pattern  of  our  modern 
mills. 

The  sharp  stone  had  many  uses.  As  a  cutting  tool  it 
was  used  to  skin  and  cut  up  game,  prepare  garments  of 
skins,  make  weapons,  etc.  (T.,  186).  These  flakes  have 
already  been  noticed  in  connection  with  the  club,  etc. 
With  rounded  but  sharp  edge,  it  formed  the  "scraper" 
for  dressing  skins,  etc.  (T.,  187). 


170  SYSTEMATIC  SCIENCE   TEACHING. 

If  heavier  and  with  broad  edge,  it  could  be  used  to 
hack  (T.,  188). 

What  modern  kitchen  tool  is  on  the  same  plan  ? 
(Chopping  knife.) 

A  long  flake  with  jagged  edge  might  be  used  as  a 
saw  (T.,  192),  and  this  improved,  made  of  metal,  and 
supplied  with  a  handle,  became  the  hand  saw  of  to- 
day. 

From  what  might  the  rasp  and  file  have  originated  ? 
(Stone  with  rough  surface.) 

The  pointed  stone,  thorn,  or  tooth  would  have  served 
w^hat  additional  purpose  ?     (Awl ;  T.,  187.) 

The  holes  having  been  made  in  the  skin  garment  or 
boat,  what  need  would  then  arise  ?  (Needle ;  of  the  Es- 
kimos, etc.,  N.  H.,  120.) 

Where  holes  were  to  be  made  in  hard  substances,  like 
stone,  the  drill  was  used  (T.,  202). 

What  were  the  steps  leading  to  the  drill  of  to-day  ? 
(1,  a  pointed  tool  revolved  between  the  hands ;  2,  the 
cord  or  thong  rapidly  wound  and  unwound  by  a  helper ; 
3,  the  cord  was  fastened  to  a  bow,  so  that  one  man  could 
work  it;  4,  when  the  drill  was  fastened  to  a  crooked 
stick  the  continuous  motion  of  the  modern '"brace"  or 
*'  bit  stock  "  was  foreshadowed.) 

(For  much  regarding  this,  see  Tylor's  Early  History 
of  Mankind,  pp.  190  and  241-248.) 

A  return  to  such  primitive  methods  is  seen  in  the 
modern  sawing  of  stone  by  soft  iron  blades  armed  with 
sand,  and  in  the  diamond  drill  of  the  miner,  or  emery 
and  diamond  dust  of  the  lapidary. 

Notebooks. — These  should  show  a  brief  record  of  the 
subject,  as  under  food.  If  the  drawing  work  of  the  pu- 
pils could  also  illustrate  such  notes,  an  exceedingly  valu- 
able record  w^ould  result,  especially  as  the  years  passed 
and  the  ingenuity  and  mechanical  skill  of  class  after  class 
resulted  in  a  museum  well  supplied  with  models. 


MAN. 


ITl 


Fire, 

Mankind  having  selected  his  food,  and  by  various 
tools  secured  it,  another  desirable  step  would  be  some 
method  of  cooking.    For  this  fire  is  needed. 

For  the  legends  and  myths  of  savages,  as  to  how  they 
first  secured  fire,  see  Longfellow's  Hiawatha  and  Tylor's 
Early  History  of  Mankind,  p.  233,  fP. 

What  was  the  probable  way  ?  (Lightning  or  the  vol- 
cano; T.,  260.) 

How  would  man  first  keep  such  fire  when  traveling  ? 
(Carry  it  along.) 

When  by  accident  it  was  lost,  how  then  ?  * 

Having  illustrated  one  way,  I  shall  now  simply  give 
the  data  in  notebook  form  : 


Fire. 

Myths  regarding  ori- 
gin. 

Probable  origin. 
Lightning  and 
volcano.  How 

spread  and  kept. 

Carried  and  cared 
for.  Ways  of  get- 
ting if  lost. 

Friction — stick  and 
groove. 

Fire  stick 

Fire  drill 

Fire  drill — bow 


People  and  Place. 

Ojibway  Indians  of 
North  America. 
Polynesia. 

AU 


Australians 


Polynesian    Islands 


Australian 

Greenlanders 

Chukchees,     north- 
eastern Asia. 


Authority. 

Longfellow,  in  Hia- 
watha (The  Peace 
Pipe);  T.  E.,  233. 

T.,  260. 


N.  H.,  30. 


T.,  261 ;  N.  H.,  30. 

T.  E.,  239  ff. 
T.  E.,  244-248. 
Voyage  of  the  Vega, 
312(Nordenskjold) 


*  In  this  same  manner  draw  out  the  pupils  after  they  have 
had  the  chance  to  inform  themselves.  Just  how  this  will  be 
done  will  differ  with  each  teacher  and  class. 


172 


SYSTEMATIC  SCIENCE  TEACHING. 


Fire. 

Pyrites  and  flint — 
tinder. 

Flint  and  steel — tin- 
der. 

Mirrors  (concave) . . . 


Burning  lens . . 
Friction  match. 


People  and  Place. 

Fuegians,         South 

America. 
Ancient       civilized 

peoples. 
Peruvians  (?),  South 

America. 
Greeks,       southern 

Europe. 
World  of  to-day. 


Authority. 
T.  E.,  249. 

T.,  263. 

T.  E.,  252,  253. 

T.  E.,  251. 


Utensils  and  Cooking. 

Fire  having  been  secured,  the  next  step  will  be  to 
trace  the  methods  of  cooking,  and  the  dishes,  etc.,  con- 
nected with  the  process. 


Modes  of  Cooking. 

People  and  Place. 

Authority. 

Raw  food 

Australians 

Eskimos,         North 
America. 

T.,  264. 

Raw  food 

T.,  265. 

Roast    or    broil    by 

Ancient        Greeks. 

T.,  266. 

fire. 

Greece. 

Roast    on    spit    to 

Savage    peoples    to 

W.,  II,  578. 

turn. 

recent  times. 

Bake  in  the  ashes  .. 

Micronesians,      Pa- 
cific Islands. 

N.  H.,  74. 

Bake  in  hot  pit 

Madagascar  Island. 

T.  E.,  263. 

Bake  with  hot  stones 

Society  Islands,  Pa- 
cific Ocean. 

N.  H.,  85  ;  T.,  267. 

Clay  oven 

Biblical  and  Oriental 

Bible  Diet.;  T.  ^ 

263. 

Brick  oven 

Old  colonial  days. 

Iron  range 

Modern. 

E., 


Those  seem  the  steps  by  which  the  modern  modes  of 
roasting  and  baking  have  been  evolved.  Boiling  seems 
to  have  been  a  later  device  to  cook  food  which  could  not 


MAN. 


173 


well  be  roasted,  and  the  interest  in  this  mode  of  cooking 
is  increased  when  we  consider  that  it  was  the  origin  of 
all  of  our  beautiful  pottery.  *  The  steps  by  which  baking 
led  to  boiling  seems  to  have  been  as  follows : 


Modes  of  Cooking. 

Boiling  by  hot  stones 

in  a  hole. 
Boiling  by  hot  stones 

in  a  skin. 
Boiling  by  hot  stones 

in  a  basket. 
Boiling  by  hot  stones 

in  wooden  bowls. 
Baskets     and    bark 

kettles  over  fire. 
Stone  vessels 

Baskets  plastered 
with  clay  to  pre- 
vent burning. 

Gourds  plastered 
with  clay  to  pre- 
vent burning. 

Wooden  bowls  plas- 
tered with  clay. 

Earthen  pot  (porous 
ware). 

Earthen  pot  var- 
nished. 

Earthen  pot  glazed. 

Copper  dishes 

Iron  kettles,  etc 


People  and  Place. 
Australian 

Assiniboin  Indians, 
North  America. 

Indians,  North 

America. 

Kamtschatdales, 
Kamchatka. 

Indians,  North 

America. 

Eskimos,  Green- 
land. 

Indians  of  North 
America. 

Indians  of  south- 
eastern North 
America. 

Indians,  South 

America. 

Kafl5r,  South  Africa. 

Peruvian     Indians, 

Peru. 

Chinese,  China 

Indians     of    North 

America. 
Civilized  nations  of 

to-day. 


Authority. 
T.  E.,  267. 

T.  E.,  265  ;  T.,  266. 

T.,  266 ;  T.  E.,  266. 

T.  E.,  267,  268 ;  T., 

266. 
T.  E.,  271. 

T.  E.,  272. 

T.  E.,  274-276;  N. 
H.,  158. 

T.  E.,  274;  T.,  274. 

T.  E.,  273  ;  T.,  274. 

W.,  I,  233. 

T.  E.,  274 :  T.,  276 ; 

N.  H.,  239. 
T.,  276. 

T.,  278. 


See  Tylor,  Early  History  of  Mankind,  pp.  265-273. 


174 


SYSTEMATIC  SCIENCE  TEACHING. 


Modes  of  Travel  and  Transportation. 

How  man  got  from  place  to  place  and  carried  his 
things  may  next  be  considered. 

By  drawing  out  the  difficulties  of  land  travel  in  a 
new  country  without  roads  or  bridges,  lead  the  class  to 
appreciate  the  reason  why  tribes  and  peoples  have  always 
settled  along  rivers  and  by  the  sea.  The  early  occupa- 
tion of  America  by  Europeans  may  well  illustrate  this, 
especially  the  French  settlements  on  the  "  portages  "  con- 
necting river  systems,  such  as  those  between  the  Great 
Lakes  and  the  Ohio  or  Mississippi. 

While  much  of  interest  might  be  found  in  the  devel- 
opment of  land  travel,  it  is  believed  that  water  travel  is 
more  typical,  and  will  illustrate  the  point  sufficiently. 
Introduce  the  subject,  and  assign  reading,  as  before. 
Thus,  in  a  thoughtful  discussion  with  the  class,  draw  out 
the  subject  in  its  natural  sequence.  Especially  try  to 
have  the  class  see  how  want  has  been  the  motive,  the 
material  at  hand  has  determined  the  method,  and  how 
one  thing  has  gradually  led  to  another. 


Mode  of  Travel. 

People  and  Coun- 
try. 

Authority. 

Log  or  branch 

Inflated  bladders  or 

T.,  252. 
T    255 

skins. 
Raft  of  rushes 

South  American  In- 
dians, Lake  Titi- 

Knox,  Boy  Travelers, 

207. 

Raft  of  logs 

caca. 
Indians,           South 

T.,  255. 

Log  and  outrigger. . 
Dug-out 

Dug-out  and  outrig- 
ger. 

America. 

Fijians,  Fiji 

Andaman     Islands, 

Bay  of  Bengal. 
Polynesians 

T.,  255. 

W.,  II,  213,  214. 

T.,  256;  N.  H.,  49, 
86. 

MAN. 


175 


Mode  of  Travel. 
Canoe  of  bark 


Canoe  of  skin 

Canoe      of      boards 


Boat     with     nailed 
boards. 

Ship 

Steamer 


People  and  Coun- 
try. 

Indians,  North 

America.  Aus- 
tralians. 

Eskimos,  Greenland. 

Melanesians 

Egypt,  northern  Af- 
rica. 

Spanish,  etc. 

United  States,  North 
America. 


Authority. 

W.,  II,  690;  T.,  254; 
W.,  II,  103. 

T.,  254 ;  N.  H.,  116. 
T.,  255 ;  N.  H.,  59, 

60. 
T.,  257-259. 


This  seems  as  far  as  it  is  advisable  to  go,  although 
it  would  be  highly  interesting  to  trace  the  development 
of  the  means  of  propulsion  from  the  hand  to  the  modern 
screw  propeller. 

We  next  study  the  development  of  shelter  from  the 
elements  and  protection  from  enemies. 

A  consideration  of  clothing  is  omitted,  as  it  would 
lead  to  embarrassing  questions  in  a  mixed  school. 

Two  factors  have  been  potent  in  this :  the  need  and 
the  available  materials  with  which  it  could  be  supplied. 

What  will  man  need  shelter  from  in  the  tropics  ? 
(Rain,  sun,  and  danger  from  animals  or  other  men.) 

What  additional  in  other  parts  of  the  earth  ?     (Cold.) 

This  subject  will  work  out  somewhat  like  the  follow- 
ing: 

Shelter  and  Protection. 


Region  and  Mode. 

Tropical  Forests. 

Screen  of  leaves  or  branches 

Circular  hut  of  leaves,  etc . . 

Huts  in  trees  to  escape  water 


People  and  Country. 

j  Indians  of  Amazon, 
(      South  America. 
Indians  of  the  Orino- 
co, South  America. 


Authority. 


I  T.,  230. 
W.,  II,  633- 


176 


SYSTEMATIC  SCIENCE  TEACHING. 


Shelter  and  Protection  {continued). 


Region  and  Mode. 

Tropical  Forests. 
Hut  on  piles  (for  protection) 

Forests  of  Temperate 

Climate. 

Bush  shelter 

Screen  of  boughs  or  grass  . . 
Circular  hut 

Bark  hut 

Hut  plastered  with  clay 

Square  or  oblong  house 

Log  house 

Frame  house 

Treeless  Plains  of  Temper- 
ate Climate. 
Tent  of  bark  or  skins 

Tent  of  cloth 

Dug-out  and  tent  roof 

Rocky  Districts. 
Caves 

Kongh  stone  screen 

Cliff  cavern  for  security 


People  and  Country. 

Dyaks  of  Borneo 

Swiss  lake  dwellers. . 


Bushmen    of    South 

Africa. 

Australian 

Bushmen    of    South 

Africa. 
Indians     of     North 

America. 
Lake     dwellers     of 

Switzerland. 
Iroquois        Indians, 

North  America. 
Early   civilized    set- 
tlers in  dangerous 

times. 
Modern  times  of  peace 


Patagonians  of  South 

America. 
Tartar  tribes,  Asia.. . 
European     peasants 

(ancient). 

Prehistoric     savages 

of  Europe. 

Australian 

Cliff   dwellers,  New 

Mexico. 


Authority. 

W.,  II,  498, 

499. 
N.  H.,  464. 

W.,  I,  274. 

T.,  230. 
W.,  I,  275.  . 

T.,  231. 

T.,  230-234 ; 

W.,  II,  861. 
N.  H.,   166; 

T.,  232. 


N.   H.,  261; 
W.,  II,  539. 
T.,  231. 
T.,  231. 

T.,  229,  230. 

T.,  232. 
N.  H.,  185. 


MAN. 


177 


Shelter  and  Protection  {continued). 


Region  and  Mode. 
Rocky  Districts. 
Rough  stone  house 


Hewn  stone 

Arctic  Climate. 
Snow  or  ice  igloo 


Skin  tent  (double) 


People  and  Country. 


Azores     of     to-day. 

Hebrides. 
Egypt    and    Mexico 

(ancient). 

EskimoSjNorthAmer- 
ica  and  Greenland. 

Chukchees,  northern 
Asia. 


Authority. 


T.,  233. 

T.,   233;  N. 
H.,  198-204. 

N.    H.,   118, 

119. 
The  Voyage 

of  the  Vega, 

288-290  ;N. 

H.,  441. 


The  evolution  of  the  brick  in  countries  having  a  very- 
dry  climate  is  set  forth  in  Tylor,  pp.  233,  234 ;  although 
the  original  suggestion  would  seem  to  have  been  the 
blocks  of  mud,  which  naturally  form  by  cracking  when 
the  bottom  of  ponds  or  rivers  is  exposed  to  long-con- 
tinued drought  (Nile  and  Euphrates). 

Language. 

The  progressive  steps  are  so  well  illustrated  by  the 
child  from  infancy  to  youth  that  I  simply  refer  to  two 
good  authorities  :  Tylor's  Anthropology,  chapter  iv,  and 
Drummond's  Ascent  of  Man,  chapter  v. 

Permanent  Expression. 

Mankind  early  felt  the  need  of  communicating  with 
the  absent  or  of  making  a  permanent  record  of  thought 
or  important  events.  How  this  want  has  developed  into 
the  beautiful  books,  paintings,  and  statuary  of  to-day  is 
exceedingly  interesting,  and  a  little  time  may  well  be 
spent  in  its  introduction. 
13 


1Y8 


SYSTEMATIC  SCIENCE  TEACHING. 


I  would  suggest  the  following  line  of  work : 


Mode  of  Expres- 

People and  Coun- 

Authority. 

sion. 

try. 

Snake  skin  and  ar- 

Indians    in     Miles 

Longfellow. 

rows. 

Standish. 

Burned  cross 

Scotch,  in  Lady  of 
the   Lake,  Canto 
III. 

Scott. 

Picture  writing 

Indians    of    North 
America.  Modern 
advertisements. 

T.,  168. 

Picture  words 

Modern  rebus 

T.,  169. 

Sound  signs 

Egyptian  and  Phce- 
nicians. 

T.,  176. 

Printing 

Chinese,  etc 

T.,  180. 

Illustrated  books... 

Modern 

Painting  in  color... 

Ancient    Egyptian. 
Modern  masters. 

T.,  303-305. 

Sculpture,  bulls,  etc. 

Assyrian  (ancient).. 

T.,  302. 

Sculpture,      sphinx, 

Egyptian  (ancient). 

T.,  300-302. 

etc 

Greece 

Sculpture,    Laocoon 
(ravth') 

Bulfinch,      Mythol- 
ogy, 281. 
Plon's  Life  of  Thor- 

Sculpture,    Lion    of 

Swiss  (modern) 

Lucerne  (history). 

waldsen,  73,  262. 

This  is  as  far  as  it  seems  wise  to  go. 

Review  in  connection  with  daily  work  in  literature, 
geography,  history,  etc. 

The  next  step  in  animal  work  is  XXXVIII— Life 
Histories. 


STEP  XXXIIL— COLLECTIONS. 

This  step  in  the  original  plan  is  omitted,  as  all  needed 
information  can  be  easily  found  elsewhere. 


STEP  XXXIV.— WINTER  QUARTERS  OF  PLANTS. 

Object. — To  introduce  the  pupil  to  a  new  and  inter- 
esting phase  of  plant  life ;  exhibit  new  relations  in  a  re- 
view of  former  lessons,  and  give  something  of  the  phys- 
ics and  chemistry  of  plants. 

Time. — About  thirty  half -hour  lessons  in  late  autumn. 
Much  of  the  work  will  be  experimental.  In  schools  with- 
out a  laboratory  it  had  best  come  after  the  other  pupils 
are  dismissed. 

Material. — Much  of  this  is  the  same  as  that  of  steps 
which  will  precede  this  in  time  (VI,  XII,  XIII,  etc.),  and 
which  it  will  be  economy  to  use.  For  a  class  of  thirty 
provide  the  following,  which  have  proved  satisfactory, 
or  make  such  substitutions  as  may  be  necessary : 

30  fleshy  taproots— turnip,  carrot,  beet,  or  parsnip. 

30  multiple  roots — asparagus,  plantain,  or  timothy 
grass. 

30  fleshy  root  stocks — potatoes,  Solomon's  seal,  or  May 
apple. 

30  corms — crocus,  spring  beauty,  or  gladiolus. 

30  coated  bulbs — onion  or  tulip ;  should  be  such  as 
will  flower. 

30  scaly  bulbs — ^lily  or  oxalis.* 

30  sections  of  endogenous  stems — cornstalk— cut  be- 
tween joints. 

*  These  roots,  etc.,  should  be  small,  but  well  formed  and 
shapely. 

179 


180  SYSTEMATIC  SCIENCE  TEACHING. 

30  sections  of  exogenous  steins— oak.    See  Step  XIII. 

30  terminal  (or  large)  buds  of  each  of  the  following : 
woolly  (hickory),  varnished  (poplar),  buried  (sumac), 
flower  (hepatica  and  hazel).     See  Step  IV. 

15  "  pulse  "  or  "  palm  "  glasses,  set  in  boards  and  with 
protecting  boxes. 

15  thermometers.     Milk  thermometers  best. 

15  bright  tin  cans — one-pound  corn  or  fruit  tins. 

15  larger  tins  to  hold  the  small  ones — two-pound  fruit 
or  tomato  cans. 

Pieces  of  variously  colored  cloth,  weighted  by  shot  in 
the  corners. 

Starch,  gluten,  dextrine,  sugar,  ether,  nitric  acid,  iodine 
solution. 

10  sets  of  experiment  cards,  as  in  Steps  XXXI  or 
XL  VIII. 

Notebooks,  one  for  each  pupil,  about  4x6  inches, 
opening  at  the  end,  and  of  at  least  fifty  pages  of  unruled 
paper. 

Preparation  of  the  Teacher.— Work  through  the  step 
before  attempting  to  give  it  to  a  class,  trying  all  the  ex- 
periments and  consulting  books  till  the  principles  in- 
volved are  thoroughly  grasped.  When  this  has  been 
done  and  the  specimens  and  apparatus  are  provided,  go 
ahead. 

While  it  is  desirable  to  follow  the  outline  of  lessons 
given  as  fully  as  possible,  teachers  with  limited  resources 
need  not  hesitate  to  give  such  part  as  a  solid  basis  of  in- 
dividual observation  and  experiment  can  be  provided  for. 

Do  not  tell  much,  but  omit  whatever  can  not  be  made 
a  matter  of  experience  or  observation  to  the  pupil. 

The  Lessons. 

1.  A  few  days  before  the  lessons  are  to  begin  ask  the 
children  to  bring  all  the  things  they  can  find  which  are 
typical  of  autumn,  such  as  colored  leaves,  fruits,  seeds, 


WINTER  QUARTERS  OF  PLANTS.     181 

roots,  etc.  With  these  decorate  the  schoolroom,  and,  if 
desirable,  have  a  public  "parents'  day"  or  harvest 
festival 

2.  While  the  decorating  is  going  on  have  the  reading 
work  center  around  autumn,  its  work,  sports,  and  beau- 
ties, and  winter  in  its  various  phases. 

3.  With  this  introduction,  now  begin  in  regular  class 
work  to  acquire  a  more  intimate  knowledge  of  these 
products  of  the  summer,  that  the  reason  for  it  all  may 
later  be  discovered.  Have  the  class  make  such  drawings 
(colored,  if  time  permits)  as  shall  with  brief  written 
notes  exhibit  the  form  and  structure  of  the  following 
things :  * 

Taproot,  whole  and  in  cross  section,  to  show  solid  in- 
terior. 

Multiple  root,  whole,  to  show  its  form. 

Root  stock,  whole  and  in  cross  section,  showing  true 
roots,  buds,  and  scale  leaves. 

Corm,  whole  (showing  leaf  scars  and  buds)  and  in  sec- 
tion to  show  solidity. 

Coated  bulb,  whole  (for  form  and  roots)  and  in  verti- 
cal and  cross  sections,  to  show  buds  and  concentric  scales. 

Scaly  bulb,  whole  and  in  both  sections,  to  show  loose 
scales  and  buds. 

Endogenous  stem,  cross  and  vertical  sections,  to  show 
woody  fibers. 

Exogenous  stem,  cross  and  vertical  sections,  to  show 
rings,  pith,  and  bark. 

Woolly  bud,  whole  and  in  enlarged  vertical  section. 

Varnished  bud,  whole  and  in  enlarged  section. 

Buried  bud,  with  the  base  of  the  leaf  stalk  which  hid 
the  bud. 

*  It  may  be  well  to  test  for  foods  (see  9)  at  the  time  the  ma- 
terial is  in  hand ;  but  it  distributes  the  experimenting  better  to 
bury  bits  in  sand  and  delay. 


182  SYSTEMATIC  SCIENCE  TEACHING. 

Hepatica  bud,  to  show  the  hairy  leaves  protecting  the 
well-advanced  flowers. 

Hazel  twigs,  showing  long  staminate  (3)  catkins  and 
rounded  (?)  buds,  all  ready  to  open  early  in  the  spring. 

These  drawings  and  notes  should  be  on  the  upper  half 
of  a  double  page  of  the  notebook,  that  later  observations, 
etc.,  may  be  added  without  turning  a  page. 

The  class  having  become  familiar  with  these  speci- 
mens and  able  to  name  them  correctly,  proceed  to 

4.  Review  the  conditions  of  plant  life  and  growth  (see 
Steps  XXIII  and  XXVIII). 

Moisture  taken  from  the  earth  by ? 

Conveyed  to  the  leaves  as  needed  by ? 

Concentration  of  crude  sap  in  the ? 

COa  decomposed  and  true  sap  elaborated  by ? 

Sap  descending  through ? 

5.  Then  bring  the  subject  before  the  class  by  qnestions. 
What  happens  to  the  delicate  root  hairs  in  winter  ? 
What  happens  to  the  leaves  ? 

To  the  sap  ? 

To  annuals  like  our  beans,  squash,  and  corn  ? 

If,  then,  the  feeding  organs  of  trees  are  destroyed  and 
many  plants  killed  entirely,  how  can  we  ever  have  them 
again? 

Expand  and  impress  this  query  till  the  class  can  see 
that  only  two  ways  are  open  : 

A.  By  the  preservation  of  the  first  (biennials  and 
woody  plants). 

B.  By  the  seeds  of  the  second  (annuals). 

A.  Preservation. 

6.  What  is  the  meaning  of  the  word  "  preservation  "  ? 
"What  are  the  dangers  to  be  guarded  against  ? 
Excessive  loss  of  heat — cold  is  only  absence  of  heat. 
Sudden    changes  in    temperature— cold    nights    and 

warm  days,  etc. 


WINTER  QUARTERS  OF  PLANTS.     183 

Excessive  moisture — rain  and  snow. 
Loss  of  natural  moisture  sap — by  evaporation. 
Delay  of  spring — ability  to  endure. 
Too  early  growth — before  settled  warm  weather. 
7.  Experiments  to  prepare  for  an  intelligent  discus- 
sion of  the  subject.* 

The  Effects  of  Evaporation. 

Experiment  1. — Cover  the  bulb  of  a  thermometer  with 
thin  cloth ;  read  and  record  the  temperature ;  then  moisten 
the  cloth  with  a  little  ether  or  alcohol,  and  holding  the 
thermometer  by  the  upper  end,  wave  it  about  gently  for 
one  minute  and  read  the  temperature  again,  t 

Why  has  the  mercury  fallen  ?  (Heat  is  needed  to 
tnm  a  liquid  to  vapor.) 

Experiment  2. — Place  a  drop  of  ether  or  alcohol  ou 
the  hand.    How  does  it  feel  ?    Why  ? 

Why  does  fanning  one's  self  cool  the  skin  ?  (Hastens 
the  evaporation.) 

Why  is  a  breeze  cooling  ?  (See  TyndalFs  Heat,  pp. 
403-414.) 

Water  coolers  are  made  in  hot,  dry  countries  by  filling 
an  unglazed  and  porous  jar  with  water  and  hanging  it  in 
the  wind  under  a  shade. 

How  does  it  work  ?  (Rapid  evaporation  from  the  sides 
of  the  jar.) 

Butter  may  be  cooled  in  dry  weather  by  placing  it  in 
a  new  flower-pot  saucer  partly  filled  with  water  and  in- 
verting a  new  and  wet  flower  pot  over  it  {in  the  water). 
Why? 

*  Each  pupil  should,  when  possible,  try  each  experiment  and 
record  his  observations.  If  this  can  not  be,  divide  the  work 
among  the  class,  so  that  the  responsibility  of  something  will  rest 
on  each. 

t  See  42,  Step  XIX. 


184  SYSTEMATIC  SCIENCE  TEACHING. 

How  does  perspiration  keep  us  from  overheating  ?  * 

Why  are  wet  clothes  or  feet  dangerous  to  health  ?  t 

How  is  ice  made  in  warm  climates  ?  J 

What  is  the  "  wet  and  dry  bulb  thermometer  "  of  the 
signal  service  ? 

Experiment  3. — Press  the  mouth  of  an  "  empty  "  bot- 
tle down  into  some  water  :  why  does  it  not  enter  ?  (Air 
can  not  escape.) 

Push  a  dry  sponge  quickly  under  water  and  then  re- 
move it.     Why  has  the  water  not  wet  it  all  through  ? 

Weigh  some  clean  corks. 

Immerse  quickly,  and  weigh  again. 

Why  have  they  gained  so  little  in  weight  ? 

Stuff  a  wide -mouthed  bottle  full  of  cotton,  wool,  or 
cork,  and  add  all  the  water  it  will  hold.  Quickly  cork 
and  invert.     After  twenty-four  hours  observe. 

What  is  in  the  top  of  the  bottle  ?    (Air.) 

Is  the  cork,  etc.,  now  wet  ? 

As  the  air  got  out,  the  water  got ?    (In.) 

In  succession  dip  the  different  kinds  of  buds  in  water 
and  record  why  the  water  wets  them  so  little. 

Immerse  an  apple.  Why  does  it  not  become  very 
wet?    (Wax.) 

Do  the  same  with  an  orange.    Why  not  wet  ?    (Oily.) 

What  ways  can  you  now  give  by  which  a  plant  keeps 
out  wet  ? 

Experiment  4. — Balance  a  sound,  uncut  potato  by  a 
pared  one. 

After  twenty-four  hours'  drying,  which  has  lost  the 
most  ? 

Why  ?    (Corky  covering  gone.) 

Take  two  similar  sound  apples  and  treat  as  the  po- 
tatoes.    Why  ?     (Waxy  covering.) 

•  See  42,  Step  XIX.  f  Hid. 

X  Encyc.  Brit.,  Ice,  or  Tyndall's  Molecular  Physics,  p.  399. 


WINTER  QUARTERS  OF  PLANTS.     185 

Do  the  same  with  two  oranges  or  lemons.  Why  ? 
(Oily  coat  gone.) 

Cut  inch-thick  sticks  of  several  green  woods  and  var- 
nish the  cut  ends.  Weigh  pairs,  and  then  split  one  of 
each  through  the  middle  and  leave  for  several  days  and 
weigh  again. 

Why  has  the  split  stick  dried  faster  ?  (Corky  layer 
broken.) 

Select  similar  pairs  of  hickory  and  of  poplar  twigs. 
Varnish  the  cut  ends  of  each,  and  then  split  one  end  open 
and  expose  both  to  the  same  air.  Which  dries  fastest  ? 
Why? 

Take  four  equal  sized  pieces  of  cotton  cloth  and  soak 
them  well  in  water.  Hang  one  in  the  sun,  one  in  the 
shade,  one  in  the  cold,  and  put  one  in  a  tin  box  or  under 
a  tumbler.    Why  do  some  dry  faster  ? 

Why,  especially,  does  the  one  in  the  tin  box  dry  so 
slowly  ? 

What  ways  do  plants  have  to  keep  the  natural  mois- 
tnre  in  ? 

Absorption  and  Radiation  of  Heat. 

After  much  experimentation  to  find  simple  ways  of 
illustrating  these  important  points  in  the  economy  of 
plant  life,  I  have  found  nothing  better  than  the  "pulse" 
or  "  palm  "  glass,  to  be  used  as  a  simple  differential  ther- 
mometer. 

Get  enough  so  that  each  pair  of  pupils  can  have  one. 
Cut  pieces  of  thick  board  about  three  inches  longer  and 
wider  than  the  pulse  glass,  and  make  a  slit  in  the  middle 
in  which  the  long  connecting  stem  may  set  freely.  This 
will  support  and  protect  the  glass,  and  the  inch  and  a 
half  on  each  end  and  side  will  permit  of  the  bulb  being 
covered  with  various  things. 

Procure  rings  or  squares  of  tin  or  cardboard  large 
enough  to  surround  the  bulb  at  the  distance  of  an  inch, 


186  SYSTEMATIC  SCIENCE  TEACHING. 

and  rising  an  equal  distance  above  the  glass.  These  may 
be  bottomless  collar  boxes,  vegetable  cans,  etc.,  but  each 
pair  should  be  similar.  Next  place  strips  of  gummed 
paper  up  and  down  on  the  side  or  end  of  the  bulbs,  so 
that  the  position  of  the  colored  liquid  can  be  marked 
when  equal  in  each  bulb,  or  when  highest  (the  other  bulb 
being  empty). 

Place  the  boards,  each  holding  a  pulse  glass,  on  a 
level  surface,  and  cause  the  liquid  to  become  equal  in 
each.  Mark  the  place  with  a  pencil  on  the  strips  of  pa- 
per. Then  in  succession  empty  each  bulb  and  mark  the 
highest  point,  as  before. 

Making  a  cut  with  a  knife  at  each  pencil  mark,  scrape 
off  all  the  rest  of  the  paper  strip,  and  then  the  equal  and 
highest  positions  of  the  liquid  will  be  easily  told,  even 
when  one  of  the  bulbs  is  concealed. 

Experiment  5. — Let  the  pupil  hold  one  (never  both  at 
once)  bulb  in  the  hand,  in  the  sun,  or  near  some  heat,  and 
learn  that  the  liquid  is  always  highest  in  the  coolest 
bulb. 

Get  the  problem  before  the  class  by  the  following 
questions: 

What  covering  do  roots  and  bulbs  have  ?  (Earth, 
snow,  dead  grass,  etc.) 

What  covering  do  buds  have  ?  (Woolly,  varnished, 
base  of  leaf,  etc.) 

What  covering  do  stems  have  ?     (Corky  bark.) 

Of  what  use  are  these  things  to  the  plant  ?  (Leave 
the  question  open.) 

Experiment  6. — In  the  following  experiments  it  is  un- 
derstood that  one  bulb  is  covered  and,  while  the  observ- 
ing is  done  on  the  uncovered  one,  the  interest  is  really  in 
the  effect  of  the  covering  on  the  other. 

The  liquid  should  be  equal  in  each  at  the  start,  and 
the  experiment  is  completed  when,  under  the  new  con- 
ditions, it  has  become  equal  again.    Use  the  rings  when 


WINTER  QUARTERS  OF  PLANTS.     187 

earth,  salt,  etc.,  is  used,  and  avoid  draughts.    Four  ex- 
periments will  be  needed  with  each  : 

a.  Warm  rooms  to  cold  (in  shade). 

h.  Cold  room  to  warm  (in  shade). 

c.  Warm  sunshine  of  rooms  to  cool  sunshine  out- 
side. 

d.  Cool  sunshine  to  warm  sunshine  of  room. 


HEAT  LOST 
(RADIATION). 

HEAT  OAINKD 
(ABSORPTION). 

Covering  op  Bulb. 

Seconds 

to  empty 

covei-ed 

bulb. 

Minutes 
to  be- 
come 
equal 
again. 

Seconds 
to  fill 

covered 
bulb. 

Minutes 
to  be- 
come 
equal 
agaiu. 

Moist  earth 

Sod  with  dead  grass 

Light  leaf  mold 

Coarse  salt  (=  snow) 

Gray  woolen  cap  (= hickory  bud) 
Loose,  brown  cotton  (sumac). . . 
Shining  paper  cap  (poplar  bud) 
Cork  or  bark  cap 

Which  coverings  radiate  heat  best  ?  Which  absorb 
best? 

What  relation  between  the  two  ?  * 

What  colors  do  we  choose  for  hats  and  clothing  in 
summer  ?    Why  light  ? 

Will  a  polished  stove  heat  better,  or  not  ?  Why 
not? 

Will  polished  shoes  be  best  in  summer,  or  winter  ? 
Why  in  summer  ? 

Would  the  kettle  boil  quicker  if  its  bottom  were 
bright  ?    Why  not  ? 

Why  did  the  gilt  sign  Tyndall  speaks  of  not  bum  ? 

Which  melts  faster,  clean  or  dirty  snow  ?    Why  ? 

*  See  Tyndall's  Heat,  pp.  301-311. 


188  SYSTEMATIC  SCIENCE  TEACHING. 

Which  colored  clothes  sink  fastest  when  laid  on 
snow  ?     (Try  and  see.) 

Explain  in  this  connection  the  difference  between 
opaque  and  radiant  heat.  Illustrate  by  a  sheet  of  glass 
over  one  bulb  of  the  pulse  glass,  the  warming  of  green- 
houses and  rooms  into  which  the  sun  shines.  See  Tyn- 
dall's  Heat,  pp.  395-422,  for  the  important  action  of  the 
watery  vapor  in  the  air. 

Why  do  clouds  tend  to  prevent  a  frost  ? 

Why  will  a  thin  cloth  protect  plants  from  a  frost  ? 

How  does  a  tree  protect  the  ground  under  and  near  it 
from  frost  ? 

Why  does  frost  form  on  the  boards  of  a  walk  and  not 
on  the  nail  heads  ?    (Iron  is  a  good  conductor.) 


Conduction  of  Heat. 

Experiment  7. — Absorption  and  radiation  of  heat  de- 
pend on  the  ability  of  the  surface  to  receive  or  release 
heat  vibrations. 

Conduction  is  the  mode  of  transmitting  these  vibra- 
tions in  from,  or  out  to,  the  surface,  and  depends  on  the 
material  composing  a  body. 

Apparatus.— To  see  how  this  compares  in  different 
substances,  take  heavy  paper  tubes  (mailing  tubes  or  old 
Eoman-candle  tubes)  of  about  an  inch  in  diameter. 

Cut  these  an  inch  longer  than  your  thermometers  are 
up  to  the  40°  F.  mark,  and  in  the  end  of  each  insert  and 
glue  inch-long  plugs  of  the  substances  in  the  following 
table.  Place  a  metal  plate  under  the  earth.  Leave  the 
"  air  "  tube  open  at  both  ends. 

Prepare  a  set  of  eight  tubes  for  each  four  pupils,  as 
they  will  need  to  work  in  pairs,  and  can  only  care  for 
four  tubes  at  a  time. 

Place  this  table  on  the  blackboard  for  all  to  copy  into 
their  notebooks : 


WINTER  QUARTERS  OP  PLANTS. 


189 


TRANSMITTED   HEAT   IN. 
COOL   CAN  IN  BOILING  WATER. 

TRANSMITTED   HEAT   OUT. 
HOT  CAN   IN   ICE  WATER. 

Seconds. 

5 

1 

a 
2 

6 

1 

3 

is 

1 

5 

1 

! 

i? 

2 

|l 

< 

1 

15 

— 

— 

30 

— 

— 

45 

60 

75 

— 

— 

— 



90 

105 

1 

— 

— 



— 

E 

120 

— 

r 

— 

— 

Average  . 

Rank.... 

1 

Which  conducted  best  ?    Which  poorest  f  * 

Do  solid,  or  porous,  substances  conduct  heat  best  ? 

Why  do  we  wear  woolen  in  winter  ? 

Why  do  fur  and  feathers  keep  animals  warm  ? 

How  do  double  windows  keep  the  house  warm  ? 

Which  are  better,  solid,  or  hollow,  walls  to  houses  ? 
Why? 

Why  do  some  animals  burrow  in  the  snow  in  cold 
weather  ? 

How  does  a  blanket  or  sawdust  keep  ice  from  melt- 
ing ? 

Explain  the  varying  sensations  of  the  bare  foot  on 
carpet,  bare  floor,  zinc,  etc. 


Tyndall's  Heat,  pp.  245-253. 


190  SYSTEMATIC  SCIENCE  TEACHING. 

8.  A  foundation  having  now  been  laid,  through  the 
study  of  plants  (3  to  6)  and  the  experiments  of  7,  the  re- 
lation and  adaptation  of  vegetable  life  to  its  environ- 
ment can  be  considered,  using  the  experiments  to  illus- 
trate and  explain. 

Let  us  now  see  the  meaning  of  what  happens  when 
winter  comes. 

Fall  of  the  leaves.    What  was  the  work  of  the  leaf  ? 

Could  this  go  on  in  winter  ?  How  does  their  fall 
help  ?  (Prevents  evaporation — while  the  root  is  resting 
— and  loss  of  heat.) 

State  of  the  buds.  Buried,  as  on  the  sumac.  How 
help? 

Woolly  scales,  as  on  the ?    How  help  ? 

Varnished  and  gummy  scales  of  the ?    How  help  ? 

Air  spaces  inside  the  buds,  as  in ?    How  help  ? 

Bulbs  and  naked  buds  ?    (Underground.) 

Bark  corky  and  scaly,  as  on ?    What  does  this 

guard  against  ?  (Loss  of  sap  and  frequent  and  sudden 
gain  or  loss  of  heat.)  * 

Why  does  the  snow  melt  slowly  on  the  north  side  of 
a  picket  fence  ? 

Under  tufts  of  grass  ?    In  the  thick  forest  ? 

Why  are  low  heads  best  for  apple  trees  in  a  change- 
able climate  ?  (The  daily  freezing  and  thawing  of  the 
south  side  of  an  exposed  trunk  cause  the  bark  to  separate 
from  the  wood  and  die.) 

Koots  and  underground  stems.  How  are  these  pro- 
tected ?    (By  earth  and  fallen  leaves.) 

The  ground  does  not  commonly  freeze  to  the  ends  of 
the  roots.    How  will  that  help  ?    (Conduction.) 

Cloudy  sky.    What  aid  ? 

Slant  rays  of  the  winter  sun.  How  help  the  plants  to 
endure  ? 

*  See  Tyndall's  Heat,  pp.  245,  246. 


WINTER  QUARTERS  OF  PLANTS. 


191 


Moist  air  of  winter.    What  aid  ? 

Snow.     How  help  ? 

9.  Stores  of  Food,— What  roots  did  we  study  ?    Stems  ? 
Bulbs  ? 

Let  us  test  for  these  foods,  and  see  what  they  are. 

Place  the  following  table  (except  the  filled-in  data)  on 
the  blackboard  for  the  class  to  copy  : 

Tests  to  recognize  Plant  Stores  of  Food. 


SUB- 
STANCE. 

Taite. 

Soluble 
in  cold 
water. 

Iodine 
test. 

Nitric- 
acid  teit. 

Oil  test. 

Ruben 

hot  paper. 

Fehling's 
soluUon. 

Chancteritttcs. 

Starch . 

starchy. 
Oily. 

No. 

No. 
No. 
Yes. 

Yes. 

Blue. 

Not  soluble  in 

Oil 

Grease 
spot. 

water,  and 
blue  with  I. 

Grease  spot  on 
paper. 

Yellow     with 

Proteids 

No. 
Violet. 

Yellow. 
No. 

Dextrin. 

Sweetish 
Sweet. 

nitric  acid. 
Sweet,  soluble. 

Sugar. . . 

Orange 
color. 

and       violet 

color  with  I. 

Tastes   sweet. 

and    orange 
with  F.  sol. 

The  starch  may  be  "laundry," ''  corn,"  or  common  flour. 

For  oil,  use  bits  of  tallow.  Rub  on  the  paper  of  the 
notebook. 

Proteids  may  be  purchased  ;  made  from  flour  by  wash- 
ing" out  the  starch,  or  use  "germ  meal,"  or  germs  of 
soaked  corn  grains. 

Dextrin  can  be  bought. 

Sugar ;  pick  grains  from  old  raisins  or  candied  honey. 

Iodine  solution ;  dissolve  1  gramme  potassic  iodide  in 
10  c.  c.  rain  water,  add  one  quarter  gramme  iodine  crys- 
tals, and  dilute  to  250  c.  c.  with  water. 

Nitric  acid,  strong ;  colors  proteids  (gluten,  albumen, 
etc.)  yellow. 

Fehling's  sugar  test ;  buy.* 

*  For  these  tests,  see  Goodale's  Structural,  Bergan's,  Bastin's, 
or  other  good  Botany. 


192 


SYSTEMATIC  SCIENCE  TEACHING. 


Use  glass  (test  tubes  or  small  vials)  for  dishes. 
After  the  class  has  learned  the  characteristic  tests,  con- 
tinue the  table. 


Wliat  Foods  do  Plants  store,  and  where. 


Part  of  Plant. 

H 

IP 

II 

Hi 

111 

What  is 
found. 

Root :  Parsnip  or  dock 

Stem :  Potato  or  Solomon's 
seal 

Stem :  Crocus  or  gladiolus . 

Bulb :  Onion  or  tulip 

Grain:  Wheat,  barley,  orcorn 

Seed :  Pea  or  bean 

Seed :  Peanut  or  sunflower. 

Sprouted  seed  :  Malt 

Grate  or  scrape  fine,  squeeze  through  cheese  cloth  in 
water,  and  set  away  for  starch  to  settle.  Pour  off  the 
clear  liquid,  test  part  of  it  for  sugar,  and  boil  a  portion, 
testing  the  scum  for  proteids  and  the  clear  portion  for 
dextrin.  Test  the  starch  with  iodine,  and  some  of  the 
original  substance  on  hot  paper  for  oil. 

What  kind  of  food  seems  most  abundant  ?  Which 
next  ?  Are  they  soluble  in  cold  water  ?  What  great 
gain  to  the  plant  from  that  ?     (Do  not  waste.) 

They  become  soluble — sugar,  etc. — in  the  same  way 
the  brewer  or  distiller  turns  starch  into  sugar. 

Illustrate  by  telling  how  the  diastase  converts  starch 
to  sugar  in  beer  and  whisky  making. 

Why  does  this  change  not  occur  in  winter  ?  (Heat  is 
needed.) 


WINTER  QUARTERS  OF  PLANTS.     193 

What  is  the  change  which  takes  place  in  the  spring  ? 
(Starch  to  sugar.) 

Illustrate  by  the  sugar  maple  ;  sugar  beet ;  rawness  of 
green  apples  and  sweetness  of  ripe;  sugar  cane  before 
the  seed  ripens ;  parsnips  in  the  spring ;  tastelessness  of 
long-kept  watermelons. 

Why  was  the  food  not  stored  as  sugar  in  the  first 
place  rather  than  insoluble  starch,  oil,  and  gluten  ? 
(Would  waste  by  osmose,  and  spoil,  as  in  making  vine- 
gar.) 

10.  Results  of  these  Preparations.— (a)  Endurance 
through  the  winter ;  (&)  early  flowers  and  leaves  ;  (c)  ac- 
cumulated growth,  giving  rise  to  varied  and  contrasted 
size,*  shape  of  head,  form  of  spray,  and  useful  timber, 
which  annuals  could  not  have. 

11.  Can  you  bring  specimens  of  trees  which  seemingly 
do  not  need  protection  ?     (Pine,  fir,  spruce,  and  cedar.) 

How  do  these  differ  as  to  leaves  and  sap  ?  Why  able 
to  endure  ? 

Note  the  great  addition  evergreens  are  to  the  land- 
scape, and  as  windbreaks. 

12.  Teacher  now  reviews  (A)  the  adaptation  of  bien- 
nials and  woody  plants  to  endure,  by  a  brief  lecture. 

B.  By  Seeds. 

13.  If  time  permits,  examine  more  seeds  than  those 
examined  in  9,  and  test  for  the  food  contents. 

What  are  the  most  abundant  food  stores  in  seeds  ? 

What  did  the  morning-glory  (XXIII)  teach  us  as  to 
the  conditions  for  germination  ?  (Heat,  moisture,  and 
oxygen.) 

Why  do  seeds  not  sprout  in  fruit  ?     (No  oxygen.) 

Why  not  in  winter  ?     (Too  cold.) 

*  See  Step  XII. 
14 


194  SYSTEMATIC  SCIENCE  TEACHING. 

Why  do  not  the  stores  waste  or  spoil  in  an  exposed 
seed  ?    (Insoluble  starch,  etc.) 

How  is  this  insoluble  food  turned  to  soluble  ?  (Di- 
astase.) 

If  nuts  or  peach  stones  are  kept  in  the  cellar  all  win- 
ter and  planted  the  next  spring  they  will  not  grow  till 
the  following  spring.    Why  not  ? 

How  are  they  gently  cracked  ?    (See  6,  Step  XX.) 

14.  What  results  from  such  seed  ?  (Prolonged  flower- 
ing season  and  rich  stores  of  food  for  animals.) 

15.  Now  hold  a  searching  oral  review  by 

1.  Each  tell  what  has  particularly  interested  him. 

2.  Give  specimens  (some  new)  to  tell  about,  as  roots, 
leaves,  seeds,  or  experiments.  Class  correct  omissions  or 
mistakes. 

3.  By  questions  from  the  teacher  covering  the  entire 
ground. 

Arrangements  should  now  be  made  for  a  supply  of 
material  for  the  Fruit  and  Com  and  Bean  lessons  next 
fall.  Divide  the  work  among  the  willing  pupils  and 
make  a  record  of  it,  to  remind  all  next  spring. 

Next  step  in  plant  work  is  XL — Fruits. 


STEP  XXXY.— WHAT  THE  TELESCOPE  REVEALS. 

Object. — 1.  To  foster  the  interest  in  astronomy. 

2.  To  study  light  in  a  simple  way. 

3.  To  increase  the  knowledge  of  our  earth. 

4.  To  prepare  the  way  for  the  study  of  rocks  (Steps 
XLIV  and  XL VIII). 

The  time  needed  will  be  about  thirty  lessons  of  thirty 
minutes  each.  Autumn  is  the  best  season  of  the  year,  as 
the  constellations  connected  with  the  story  of  Perseus 
can  be  best  seen,  and  the  others  appearing  at  that  time 
reviewed. 

Material  needed. — Such  lenses  of  different  kinds,  mir- 
rors, spy  or  field  glasses  and  telescopes,  as  may  be  avail- 
able.   Also  a  prism  and  the  few  chemicals  spoken  of. 

As  in  all  my  suggestions,  the  best  is  advised,  but 
much  can  be  omitted,  and  a  very  simple  and  inexpensive 
set  of  apparatus  made  to  do  good  work.  The  reading 
suggested  below  will  indicate  what  things  are  needed 
and  how  to  use  them.  I  shall  suppose  the  place  to  be  the 
ordinary  light  schoolroom.  Those  who  can  have  a  dark 
room  will  be  able  to  add  much  of  interest  to  the  class 
work. 

Preparation  and  Literature.— Read  the  chapter  on 
Light  in  any  good  work  on  physics  of  recent  date ;  Miss 
Buckley's  Through  Magic  Glasses ;  also  pages  226-239  and 
263-271  in  Lockyer's  Astronomy.  Make  yourself  famil- 
iar with  what  the  class  has  studied,  the  previous  steps  in 
astronomy,  and  the  molecule  lessons  in  this  book.    Then 

195 


196  SYSTEMATIC  SCIENCE  TEACHING. 

read  through  this  step,  try  all  the  experiments,  and  mod- 
ify as  may  seem  best. 

Outline  of  the  Step. 

1.  Connection  by  review  questions. 

2.  Light  a  mode  of  motion,  with  a  wave  front. 

3.  Moves  in  straight  lines.     Eay. 

4.  Light  itself  is  invisible,  but  makes  other  objects 
seen. 

5.  Its  brightness  varies  inversely  as  the  square  of  the 
distance. 

6.  Things  are  transparent  or  opaque. 

7.  Light  falling  on  opaque  objects  is  absorbed  or  re- 
flected. 

8.  The  angle  at  which  light  is  reflected  is  equal  to  that 
at  which  it  strikes. 

9.  Concave  mirrors  gather  the  light  to  a  bright  focus. 

10.  Light  moves  slower  in  dense  than  in  rare  media. 

11.  When  rays  pass  obliquely  from  one  medium  into 
another  the  direction  is  changed. 

12.  Convex  lenses  gather  the  light  to  a  focus. 

13.  Dim  and  distant  objects  can  be  seen  better  by  the 
aid  of  certain  mirrors  or  lenses. 

14.  Some  of  the  things  better  seen  by  the  aid  of  tele- 
scopes and  field  glasses. 

15.  Are  nebulae  distant  clusters  of  stars  ?  Laplace's 
hypothesis. 

16.  Only  gases  and  vapors  burn  with  a  flame. 

17.  All  things  can  be  vaporized.     Steel  making. 

18.  Each  element  has  a  flame  color  of  its  own. 

19.  Each  color  is  diflPerently  bent  (refracted)  by  a 
prism,  and  when  mixed  can  be  separated  into  a  spec- 
trum. 

20.  The  spectroscope  a  contrivance  to  do  this  sepa- 
rating well. 


WHAT  THE  TELESCOPE  REVEALS.  197 

21.  White  light  is  composed  of  united  waves  of  col- 
ored light. 

22.  The  spectra  of  glowing  solids  and  liquids  are  con- 
tinuous bands,  while  the  spectra  of  glowing  gases  and 
vapors  have  lines. 

23.  Laplace's  nebular  hypothesis. 

24.  Some  proofs  Laplace  had.  * 

25.  What  the  spectroscope  adds. 

2Q.  Constellations  and  the  story  of  Perseus. 

While  well  aware  of  the  wide  range  of  this  outline, 
I  am  confident  it  can  be  successfully  covered  in  thirty 
school  lessons  by  the  prompt  and  steadily  progressive 
work  which  alone  will  enable  the  children  to  keep  the 
connection.  Do  not  bring  in  other  matters  ;  they  will 
be  provided  for  elsewhere. 

1.  Connecting  Questiona— Do  lifeless  bodies  have  the 
power  to  start  or  stop  themselves  ? 

What  is  a  force  always  acting,  ready  to  cause  motion 
if  not  prevented  ?     (Gravitation.) 

Through  what  distances  does  it  act  ?     (All.) 

On  what  things  ?  (AZZ,  from  the  sand  grain  to  the 
huge  sun.) 

Is  it  equally  strong  at  all  distances  ?  (No ;  it  grows 
weaker  as  the  distance  increases.) 

Can  a  body  like  a  ball  or  planet  have  more  than  one 
motion  at  a  time  ?     (Yes.) 

Which  way  will  it  move  under  this  compound  motion  ? 
(In  a  direction  intermediate  between  the  two  directions.) 

What  will  these  conflicting  forces  tend  to  do  ?  (Strain 
the  body,  and,  if  able,  change  its  shape  or  break  it  in 
pieces.) 

What  benefit  is  this  attraction  of  gravitation  to  us  ? 
(Holds  us  and  all  things  on  the  earth's  surface.) 

Why  do  meteorites  come  to  the  earth  ?     (Gravitation.) 

Why  do  they  burn  up  ?  (Friction  of  the  air  as  they 
pass.) 


198  SYSTEMATIC  SCIENCE  TEACHING. 

What  shows  that  the  earth  attracts  the  moon  ?  (Does 
not  fly  off.) 

What  shows  that  the  moon  attracts  us  ?    (Tides.) 

Why  do  the  tides  rise  higher  twice  a  month  ?  (Sun 
helps  the  moon.) 

Why  do  we  not  fall  to  the  sun  ?  (We  are  continually 
falling  toward  the  sun,  but  have  an  onward  motion, 
which  as  constantly  carries  us  to  one  side.) 

The  Lessons. 

2.  Place  a  lighted  candle  before  the  class. 

In  how  many  ways  does  the  light  shine  ?     (All.) 

Blow  a  soap  bubble.  In  how  many  ways  does  it 
spread  ? 

We  think  that  when  anything  gives  light,  waves  of 
motion  start  from  it  and  spread,  as  the  soap  bubble  did, 
the  shell-like  waves  spreading  out  more  and  more  as 
they  go  out  from  the  center. 

(Blow  another  bubble,  and  talk  of  it  till  this  spread- 
ing motion  is  clear). 

An  electric  light  hangs  over  a  road.  Tell  me  how 
many  ways  its  waves  of  light  spread.  (Up,  down,  north, 
south,  east,  and  west.) 

Yes,  and  all  the  intermediate  directions,  like  a  bird's 
song  in  the  air. 

Why  do  I  say  "  waves "  ?  (Because  the  shell-like 
waves  continue  to  start  from  the  candle  or  other  shining 
thing  one  after  another,  just  as  though  one  soap  bubble 
within  another  could  start  from  this  pipe.) 

Now,  different  pupils  tell  me  what  light  is.  (Light  is 
a  kind  of  motion.) 

3.  Who  has  seen  lines  of  light  in  a  dark  barn  or 
room  ? 

What  do  you  remember  about  them  ?  (Saw  dancing 
specks.) 


WHAT  THE  TELESCOPE  REVEALS.  199 

What  were  these  specks  ?    (Dust.) 

Where  did  the  light  come  from  ?    (Some  hole.) 

What  became  of  the  rest  of  the  sun  or  other  light  ? 
(Was  kept  on  the  other  side  by  the  boards  of  the  barn, 
etc.) 

Were  these  lines  of  light  straight,  or  crooked  f 
(Straight.) 

Can  you  see  around  a  corner  ? 

Through  a  curved  or  bent  tube  ? 

How,  then,  does  the  little  portion  of  shell-like  motion 
which  enters  your  eye  from  anything  you  see  travel  ? 
(Straight.) 

If,  then,  we  should  take  any  tiny  portion  of  the  shell- 
like wave  from  a  light  and  follow  the  center  off  as  far 
as  it  went,  in  what  direction  would  it  move  ? 

Light  moves  in  straight  lines,  and  each  line  of  direc- 
tion is  called  a  ray. 

4.  Let  us  next  consider  what  it  was  you  really  saw  in 
the  dark  barn  or  room.  Professor  Tyndall  tried  two  in- 
teresting experiments.  He  put  a  hot  flame  under  such  a 
beam  of  light,  and  a  pitchy  black  place  appeared  over 
the  flame. 

He  next  took  a  tight  box  with  small  glass  windows  in 
three  sides,  and,  having  passed  a  strong  beam  of  light 
through  the  end  windows,  viewed  it  through  the  side  one. 
It  looked  as  yours  did  in  the  barn.  He  now  painted  the 
inside  of  the  box  with  glycerin  (which  does  not  dry  like 
water),  and,  closing  it  tightly,  set  it  aside  for  some  time, 
after  which  a  beam  of  light  passed  through  the  ends 
could  not  be  seen  at  the  side. 

What  change  could  have  taken  place  in  the  box  ? 
(The  dust  had  been  caught  by  the  glycerin.) 

In  the  beam  over  the  flame  ?  (The  dust  had  been 
burned  up.) 

What  was  it  you  really  saw  in  the  barn  ?  (Shining 
dust.) 


200  SYSTEMATIC  SCIENCE  TEACHING. 

Why  was  the  light  invisible  over  the  flame  and  in  the 
box  ?    (No  dust.) 

Can  light  which  does  not  enter  the  eye  be  seen  ? 
(No.) 

How  would  the  sky  look  if  no  dust  or  watery  vapor 
were  in  it  ?     (Black.*) 

5.  Is  a  distant  lamp  as  bright  as  a  near  one  ?  (Yes, 
but  it  does  not  appear  so.) 

Why  does  it  strain  and  tire  your  eyes  to  read  at  a  dis- 
tance from  a  lamp  ?     (Dim  light.) 

Darken  the  windows  the  best  you  can  while  I  light  a 
candle  and  place  it  eight  feet  from  the  blackboard.  Now, 
watch  the  shadow  of  this  square  book.  I  place  it  one 
foot  from  the  candle.  Mary  may  mark  on  the  board  the 
boundaries  of  tlie  huge  shadow.  I  place  the  book  two 
feet  from  the  candle  and  mark  the  smaller  shadow.  Now 
three  feet  from  the  candle  and  again  mark. 

What  is  this  shadoiv  f  (The  dark  space  behijid  some- 
thing that  stops  the  light.) 

When  was  the  most  light  cut  ofl'  ?  (When  the  book 
was  near  the  candle.) 

When  did  the  book  stop  the  least  light  ?  (When  far- 
thest from  the  candle.) 

Now  open  the  blinds  and  let  us  measure  the  shadows, 
the  last  one  first. 

Taking  this  as  our  measure,  how  many  times  is  it  con- 
tained in  the  two-foot  shadow  ?     (Four  times.) 

In  the  three-foot  shadow  ?     (Nine  times.) 

So  the  portion  of  expanding  light  wave  stopped  by 

the  book  at  one  foot,  at  two  feet  had  spread  over 'i 

(Four  times  the  space.) 

At  three  feet  ?    (Over  nine  times  the  space.) 

If  the  brightness  at  one  foot  be  represented  by   1, 

*  See  Tyndall's  Molecular  Physics,  pp.  341,  842,  and  Frag- 
ments of  Science,  p.  294. 


WHAT  THE  TELESCOPE  REVEALS.  201 


* 


at    two    feet    it    would    be ?      (J.)      And    at    three 

feet?    (i) 

Just  as  though  I  had  3  balls  of  butter  to  spread  on 
some  bread.  I  spread  the  first  on  one  slice.  The  second 
on ?     (Four  slices.)    The  third  on ?    (Nine  slices.) 

Now,  this  is  what  is  meant  by  saying  light  varies 
inversely  as  the  square  of  the  distance. 

6.  In  turn,  name  substances  on  which  light  falls. 
Kate  and  Sarah  may  write  them  on  the  board  as  I  tell 
them  to.  "  Glass  " — Kate  writes.  ''  Wood  " — Sarah  writes. 
"  Chalk  " — Sarah  writes.     '"  Water  " — Kate  writes,  etc. 

Wliat  word  shall  we  write  over  glass  and  things  which 
permit  light  waves  to  pass  through  them  ?  (Transpar- 
ent.) 

And  over  Sarah's  long  list  ?     (Opaque.) 
What  does  that  word  mean  ?     (Stops  the  light.) 
Will  all  things  fall  more  or  less  perfectly  under  these 
two  heads  ?    Yes,  we  can  then  say,  "  Things  are  trans- 
parent "  or  "  opaque." 

7.  If  you  look  from  a  light  room  into  a  dark  one,  or 
down  a  long  dark  hall,  what  do  you  see  ?     (Nothing.) 

How  would  a  deep  hole,  like  a  mine  shaft,  look  ? 
(Black.) 

Boys  sometimes  cut  faces  in  pumpkins  and  put  a  light 
inside.  If  one  came  toward  you  in  the  dark  would  you 
see  the  pumpkin,  or  the  face  f    (The  face.) 

Which  would  you  really  see  in  the  dusk  of  evening, 
the  blackboar^d,  or  the  white  icriting  f  The  printing  on 
that  chart,  or  the  spaces  between  the  letters  ?  (White 
spaces.) 

Do  you  really  see  the  letters  in  your  reading  book  or 
a  newspaper  ?     (No.) 

Now,  light  waves  were  going  into  the  dark  room  and 
down  the  mine,  and  just  as  many  fall  on  the  blackboai'd 
and  black  letters  of  your  book  as  on  the  white  paper  and 
letters. 


202  SYSTEMATIC  SCIENCE  TEACHING. 

What  is  the  difference  ?  (The  dark  holes  had  noth- 
ing in  them  for  the  light  to  fall  on — like  TyndalFs  box 
after  the  dust  had  settled  ;  and  the  blackboard  and  letters 
kept— or,  as  we  say  absorbed — the  light.) 

How  about  the  things  we  really  see  ?  (The  light 
waves  that  fall  on  them  are  turned  to  our  eyes.) 

Now  this  will  help  you  to  understand  my  words  when 
I  say,  "Light  falling  on  opaque  objects  is  absorbed  or 
reflected." 

8.  How  this  sending  off  a  reflection  takes  place  we 
will  now  consider. 

A  ball  thrown  straight  down  bounces ?    (Up.) 

If  thrown  at  an  angle  ?    (Glances  away.) 
A  stone  is  dropped  toward  water  ?     (Enters.) 
When  thrown  at  an  angle  ?    (Skips  or  glances.) 

We  stand  in  front  of  a  mirror  and  see ?     (Our 

own  faces.) 

We  stand  at  one  side  and  see ?     (Things  on  the 

other  side.) 

Let  us  try  some  experiments  about  this.  You  may 
copy,  while  I  draw  near  the  top  of  the  board,  this  straight 
line,  116  cm.  long.  From  its  center,  with  a  radius  of  58 
cm.,  I  will  draw  this  semicircle  below  it. 

What  will  be  the  length  of  the  semicircumference  ? 
il  X  3.14  X  116  =  182.12  cm.) 

How  many  degrees  in  half  a  circle  ?  (180°.) 
So  each  cm.  of  arc  will  nearly  correspond  to  1°. 
Draw  a  perpendicular  from  the  center  through  the  mid- 
dle of  the  semicircle.  Now  begin  on  one  side  of  this  per- 
pendicular and  mark  off  5  cm.  of  arc.  Do  this  ten  times 
on  that  side,  and  then  begin  at  the  center  again  and  do 
the  same  on  the  other  side.  Next  draw  20  lines  from  the 
center  through  these  20  points  and  as  far  beyond  the 
circle  as  you  can.  Each  one  of  the  20  little  arcs  made 
will  measure  an  angle  at  the  center  of  how  many  de- 
grees ?    (5°.) 


WHAT  THE  TELESCOPE  REVEALS.  203 

Beginmng  on  each  side,  mark  the  first  line  "  5°,"  the 
second  "  10°,"  and  so  on  up  to  50°.  I  wiU  stick  this  large 
headed  pin  at  the  end  of  the  perpendicular  line  and  hold 
this  bit  of  mirror  just  at  the  center.  The  light  waves 
from  the  sun  (or  candle)  fall  on  the  pin  and  are  reflected 
to  the  mirror.  The  mirror  sends  them  along  which  line  ? 
Vary  this  by  putting  the  pin  (or  any  small  object)  on 
other  lines  and  at  other  distances.  See  what  line  the  re- 
flected light  follows,  and  read  the  angles.  Here  are  small 
pieces  of  mirror  I  will  lend  you.  After  school  each  draw 
one  of  these  semicircles  on  thick  paper  pinned  to  a  board, 
or  even  on  the  board,  sand,  or  any  proper  place,  and  find 
out  how  the  angle  of  incidence  (at  which  the  light  strikes 
a  reflecting  surface)  compares  with  the  angle  of  reflection 
(at  which  it  is  sent  ofl^). 

(The  next  lesson.)  I  should  like  to  hear  from  dif- 
ferent ones  as  to  what  they  did  and  observed.  (Class 
tell  results,  etc).  Then  what  shall  we  conclude  about 
the  rebounding  (reflection)  of  light  ?  (That  "  the  angle 
of  incidence  is  equal  to  the  angle  of  reflection.") 

Where  are  these  angles  measured  from  ?  (A  perpen- 
dicular to  the  plane  of  reflection  or  to  the  surface  that 
reflects.)     (Teacher  explain.) 

9.  Why  do  lamps  have  reflectors  ?  (To  turn  much  of 
the  light  toward  some  place  or  direction.) 

What  is  the  shape  ?     (Concave.) 

Here  is  a  curved  line  to  represent  the  concave  re- 
flector, and  these  parallel  lines  going  to  it  we  will  call 
rays  of  light.  Which  way  will  they  travel  after  reflec- 
tion ?  (Inward  a  little.)  In  which  case  they  will  at  last 
meet  at  a  point  called  the  focus. 

Why  does  the  light  from  a  reflector  seem  so  bright 
when  the  eye  is  in  its  range  ?  (There  are  many  rays 
turned  so  as  to  enter  the  eye  at  the  same  time — i.  e„  the 
reflector  concentrates  the  rays  on  the  point  where  the 
eye  is.) 


204  SYSTEMATIC  SCIENCE  TEACHING. 

Going  down  the  Mississippi  River  on  a  steamboat  at 
night  I  was  much  interested  in  the  way  the  pilot  used 
his  "  search  light "  to  find  the  objects  on  shore  by  which 
to  steer.  A  large  concave  reflector  on  the  bow  of  the 
boat  threw  the  rays  of  a  powerful  light  in  one  straight 
beam.  An  endless  rope  enabled  him  to  turn  this  in  any 
desired  direction,  making  the  objects  on  which  the  pow- 
erful beam  fell  clear  as  noonday.  In  this  case  the  light 
was  at  the  focus,  and  so  the  beam  of  light  went  out  in 
parallel  rays.  Let  us  imagine  the  light  removed  and  the 
eye  placed  at  the  focus  ?  (The  gathered  rays  would  cause 
dim  objects  to  look  brighter,  and  distant  objects  more 
distinct.) 

Sitting  in  a  scientist's  parlor  one  evening  the  lights 
were  put  out,  and  when  our  eyes  had  become  used  to  the 
darkness  we  could  barely  distinguish  the  objects  outside 
an  open  window.  Our  host  then  placed  on  the  table, 
facing  the  window,  a  slightly  hollowed  plate  of  polished 
metal  he  had  been  making  for  a  telescope.  To  our  de- 
light on  looking  at  it,  trees  and  other  objects  became 
beautifully  distinct.  What  caused  it  ?  Would  such  a 
reflector  be  helpful  in  looking  at  the  moon  or  stars  i 
How? 

10.  Substances  are  said  to  be  rare  or  dense  accord- 
ing as  their  molecules  are  widely  scattered  or  close  to- 
gether. 

Name  something  transparent,  denser  than  air.    (Glass.) 

Rarer  than  glass  ?     (Water.) 

Rarer  than  air  ?     (Ether  of  space  ) 

A  stone  is  dropped  into  water,  or  a  bullet  fired  straight 
into  wood.  As  these  leave  the  rare  air  and  pass  through 
the  denser  water  or  wood,  how  will  they  move  ?  (Straight 
on,  but  slower.) 

Why  slower  ?  (Denser  substance  is  harder  to  pass 
through.) 

Suppose  I  stood  on  a  high  bridge  and  dropped  the 


WHAT  THE  TELESCOPE  REVEALS.  205 

stone  on  some  thin  ice  ?  (Would  be  checked  by  the  ice, 
but  go  faster  again  in  the  water  below.) 

Air,  water,  glass,  and  other  substances  which  permit 
light  to  pass  through,  we  call  media.  Experiments — 
which  we  can  not  make — have  proved  that  light  waves 
move  slower  in  a  dense  than  in  a  rare  medinm. 

11.  In  what  is  to  follow,  each  must  keep  clearly  in 
mind  the  double  motion  of  a  light  wave.  Not  only  is  it 
moving  on  in  a  straight  line,  but  the  spherical  wave 
front  is  also  spreading  out  in  all  directions  at  right 
angles  to  this  onward  motion. 

Does  air  hinder  your  walking  or  running  ?     (A  little.) 

How  about  water  ?     (More.) 

Did  you  ever  run  down  the  beach  into  the  water  ? 
What  was  the  effect  of  your  feet  entering  the  water  first  ? 
(Nearly  tripped  forward.) 

Why  ?  (Feet  were  held  back  by  the  water,  while  the 
body  tried  to  keep  on.) 

Which  way  is  a  man  apt  to  fall  on  jumping  from  a 
moving  wagon  or  train  ?  (Forward,  the  way  the  train 
moves.)     Why  ? 

Which  way  do  men  on  the  top  of  rapidly  inoving 
freight  cars  lean  ?     (Forward.) 

Why  ?  (Wind  makes  them  unable  to  stand  up 
straight  without  danger  of  falling  backward.) 

Why  does  a  wave  "  break "  on  the  beach  ?  (Lower 
part  is  retarded  by  the  bottom,  while  the  upper  portion, 
continuing  its  motion,  pitches  over  forward  in  a  crest  of 
foam.) 

Should  the  wave  strike  a  pier  or   pile,   what ? 

(Will  reunite  beyond  it,  and  go  on.) 

Will  this  reunion  be  quietly  made  ?  (No ;  with  more 
or  less  confusion.) 

What  is  there  in  the  vast  space  through  which  the 
earth  and  moon  travel  ?  (Nothing  as  dense  as  air,  but 
there  does  seem  to  be  a  something  able  to  carry  the  heat 


206  SYSTEMATIC  SCIENCE  TEACHING. 

and  light  waves,  and  still  so  very,  very  rare  as  not  to  re- 
tard to  any  measurable  extent  the  huge  bodies  which 
rush  through  it.) 

We  call  this  very  thin  medium  ether. 

Now,  light  waves  pass  through  this  ether— sls  we 
found  from  Jupiter's  moons — how  fast  ?  (186,000  miles 
a  second.)     (See  page  10.) 

Will  it  pass  as  fast  through  air  ?    (No.) 

Through  water  ?    (Slower.) 

Glass  ?    (Slower  still.) 

If  the  waves  of  light  pass  straight  from  a  rare  sub- 
stance (air)  into  a  dense  medium  like  water  or  glass,  what 
will  happen  ?     (Go  straight  on  with  a  changed  velocity.) 

Think  carefully  before  you  answer  the  next  question. 

Suppose  the  ray  enters  at  an  angle,  so  that  the  bottom 
(for  example)  of  the  spherical  wave  front  strikes  the 
water  or  glass  before  the  top  ?  (The  wave  will  trip,  like 
the  boy  in  rapid  motion  whose  feet  suddenly  are  retarded 
by  water,  or  like  the  crest  of  a  "  breaker.") 

How  about  the  direction  of  motion  ?  (Will  be 
changed.) 

There  is  an  illustration  which  has  been  very  useful  to 
me.  You  have  seen  a  pasture  where  the  grass  was 
smoothly  eaten  down:  is  it  easy  to  walk  on  such  a 
place  ?  We  will  suppose  a  company  of  soldiers  had 
camped  in  this  pasture,  and  for  their  camp  fires  had  carried 
away  the  fence  from  a  field  of  tall  gi'ain  *  which  pushed 
a  corner  out  into  the  pasture.  Suddenly  the  men  were 
formed  in  line  and  ordered  to  march  as  rapidly  as  pos- 
sible in  a  direction  which  took  them  across  the  corner  of 
the  field.  As  the  column  came  to  the  tall  grain  one  end 
of  the  line  got  into  the  thick  grain  first,  and  while  strug- 
gling through  it  the  end  on  good  walking  got  along  fast- 
er, and  when  at  last  all  were  in  the  grain  the  direction  of 

*  Beep  mud  will  do  as  well. 


WHAT  THE  TELESCOPE  REVEALS. 


207 


march  had  swung  a  little  toward — what  ?     (The  tvidest 
part  of  the  corner  of  grain.) 

After  a  while  the  men  began  to  get  out,  but  those  last 
in  were  first  out,  and  so  kept  gaining,  and  the  front 
changed  a  second  time. 
We  will  all  draw  this. 
P  will  represent    the     ^ 
field,    A    the    column 
when  it  started,  B  the 
column  when  all  were 
in,   and    C  when    all 
were  out. 

Toward  which  part 
of  the  field  did  the  di- 
rection change  each 
time  ?     (Widest  part.) 

I  trust  you  now  understand  that  when  a  ray  of  light 
passes  obliquely  from  one  medium  to  another  its  direction 
is  changed. 

12.  Suppose  a  shallow  pond  were  lens-shaped — thick- 
est in  the  middle — and  a  line  of  men  marched  through 
as  rapidly  as  they  could.  (The  end  men  would  close  in 
upon  the  center  ones,  and,  if  each  kept,  on  would  meet  in 
a  group.) 

What  that  we  have  talked  of  does  this  gathering 
together  remind  you  of  ?  (The  focusing  of  the  rays  by  a 
concave  mirror.) 

Here  are  some  lenses  for  you.  Where  are  they  all 
thickest  f    (In  the  middle.) 

Now,  remembering  what  we  have  talked  of,  take  them 
and  experiment  till  the  next  lesson. 

What  have  you  learned  with  your  lenses  ?  (Near 
things  look  larger.  The  light  is  brighter  at  the  focus. 
Distant  things  look  small  and  inverted.  The  lenses 
gather  the  heat,  and  answer  for  burning  glasses.) 

Good  !    These  are  all  important  observations,  and  all 


208  SYSTEMATIC  SCIENCE  TEACHING. 

the  better  because  I  did  not  help.  Are  the  lenses  larger 
than  the  pupils  of  our  eyes  ?  Can  you  think  of  any 
service  such  lenses  can  be  to  us  in  our  star  studies  ? 
(Make  stars  and  moon  brighter  and  clearer.) 

In  what  position  will  they  appear  ?    (Upside  down.) 

And  in  size  f     (Smaller.) 

Convex  lenses  gather  the  light,  and  two  or  more  of 
them  may  make  distant  objects  look  larger  and  more 
distinct. 

Keep  your  lenses  and  try  some  of  these  things  again. 

13.  Telescopes  and  Field  Glassea— Name  a  way  to 
make  dim  or  distant  objects  more  distinct  ?  (By  two  or 
more  lenses  of  different  focal  lengths  properly  com- 
bined.) 

There  are  many  ways  of  fixing  these  mirrors  and 
lenses,  which  you  will  find  described  in  books  on  physics 
or  astronomy.  By  the  aid  of  the  cuts  in  these  some  of 
you  may  be  able  to  construct  simple  instruments  to  ob- 
serve near  or  distant  things. 

14.  Now  have  the  class  gather  on  clear  evenings  with 
all  the  helps  they  can  bring,  and  observe  as  many  as  pos- 
sible of  the  following  objects.  Compare  on  the  spot  with 
the  cuts  and  descriptions  in  books  suggested  in  the  open- 
ing pages  of  this  step. 

1.  The  moon.     (See  Magic  Glasses,  pp.  10-23.) 

2.  The  phases  of  Venus. 

3.  The  disk  and  moons  of  Jupiter. 

4.  Saturn  and  rings.     (Lockyer,  p.  148.) 

5.  Some  double  star.     (Mizar  in  the  "  dipper.") 

6.  A  star  cluster.  (Lockyer,  p.  47,  or  Magic  Glasses, 
p.  163.) 

7.  A  nebula — that  in  Andromeda.  (Magic  Glasses, 
p.  163.) 

15.  The  star  clusters  and  nebnlae  looked  so  much  alike 
at  first  that  they  were  all  supposed  to  be  clusters  of 
stars,  so  very  distant  as  not  to  be  separately  seen.    The 


WHAT  THE  TELESCOPE  REVEALS.  209 

famous  astronomer  in  whose  honor  the  sign  of  Uranus 
was  made  ^  (an  H  with  a  planet  suspended  from  the 
crossbar)  studied  these  clusters  and  nebulae  with  much 
care,  and  discovered  many  new  ones.  As  Herschel  ob- 
served and  catalogued  these,  the  idea,  before  suggested 
by  others,  that  some  were  not  clusters,  grew  in  his  mind. 
What,  then,  were  they  ?  Simply  glowing  gases,  and 
our  own  solar  system  was  once  a  nebula.  Later,  this 
thought  was  taken  up  and  written  about  by  a  brilliant 
Frenchman  named  Laplace,  whose  conception  of  how  a 
hot  central  sun  like  ours,  surrounded  by  planets  and 
their  moons,  came  into  being,  is  known  as  the  nebular 
hypothesis  of  Laplace.  His  conception  (or  idea)  is  more 
and  more  accepted  by  men  of  science,  and  I  want  you  to 
know  something  of  this  wonderful  and  helpful  story. 
Let  us  get  a  few  needed  conceptions  first. 

16.  Only  gases  and  vapors  bum  with  a  flame. 

Name  some  things  which  burn  with  a  flame.  (Wood, 
oil,  coal,  gas,  tallow,  etc.) 

Is  it  wood  (and  coal)  which  darts  and  flashes  up  the 
chimney  or  rushes  in  hissing  jets  from  the  cracks  ?  Can 
solids  behave  so  ?  (No,  only  the  gases  into  which  the 
heat  turns  them.) 

So  with  the  candle,  and  all  other  things. 

Before    w^e    have   flame ?      (We    must    have    a 

gas.*) 

17.  Cast  iron  is  very  impure  and  brittle.  It  has  been 
found  that  the  cheapest  way  to  make  the  hard,  tough 
steel  used  for  rails,  etc.,  is  to  melt  the  iron,  burn  out  all 
the  sulphur,  carbon,  sand,  lime,  and  other  things  mixed 
with  it,  and  then  add  to  the  purified  iron  just  enough  of 

*  The  teacher  should  now  take  the  class  to  some  Bessemer 
steel  works  to  observe.     If  this  is  impossible,  gather  cuts  and 
illustrations  from  chemistries  or  other  sources  and  make  the  idea 
as  vivid  as  possible  by  words. 
15 


210  SYSTEMATIC  SCIENCE  TEACHING. 

the  carbon,  which  miist  be  present  with  it  to  make  good 
steel. 

This  is  the  way  it  is  done:  A  huge  one-sided  pot, 
called  a  "converter,"  is  made  of  iron  and  lined  with  fire 
brick — as  our  stoves  and  grates  are — to  keep  it  from  melt- 
ing. The  bottom  of  this  converter  is  full  of  holes  about 
the  size  of  one's  finger.  These  holes  all  end  in  a  cham- 
ber connected  with  powerful  air  pumps  called  "com- 
pressors," which  can  send  a  blast  of  hot  air  at  such  a 
furious  rate  through  the  holes  that  even  good-sized  stones 
would  be  sent  flying  out  at  the  mouth  if  they  chanced  to 
be  in  the  way  of  the  blast. 

This  converter  is  hung  like  one  of  those  urns  used  to 
make  tea  on  the  table,  so  that  it  will  tip  up  or  down. 

When  all  is  ready  this  giant  pot  is  tipped  till  the 
mouth  opens  at  the  side,  and  into  the  huge  bulge  below 
is  poured  about  half  a  car  load  of  melted  iron. 

The  blowholes  in  the  bottom  are  opposite  the  mouth, 
and  so  this  pond  of  molten  metal  does  not  rise  to  them. 

A  signal  is  given,  the  huge  compressors  start,  and  as 
the  whirlwind  of  hot  air  sweeps  through  the  tubes  in  the 
bottom  and  over  the  surface  a  shower  of  bright  sparks 
fills  the  air.  The  converter  now  begins  to  slowly  turn, 
and  as  the  mouth  rises  to  a  hole  in  the  iron  roof  above,  the 
melted  metal  flows  over  the  holes  in  the  bottom  and  the 
blast  of  air  bubbles  up  through  and  rushes  with  a  deaf- 
ening roar  of  flame  from  the  mouth.  This  is  kept  up  ten 
or  fifteen  minutes,  and  while  we  are  waiting  to  see  the 
end  let  us  think  (no  one  could  hear)  what  is  in  that 
flame. 

As  the  blast  of  hot  air  rushes  through  the  melted  mix- 
ture the  iron,  sand,  lime,  and  other  things  become  va- 
pors, which  burn  on  coming  to  the  air,  like  any  other 
gas,  and  that  flame,  so  bright  that  we  can  hardly  look  at 
it,  is  made  by  the  glowing  vapors  of  these  things.  As  the 
time  passes  the  small  quantities  of  injurious  sand,  sul- 


WHAT  THE  TELESCOPE  REVEALS.  211 

phur,  lime,  and  carbon  disappear  in  flame  along  with 
some  of  the  iron. 

When  the  color  of  the  flame  shows  that  little  besides 
iron  is  burning",  the  converter  slowly  turns  back  till  the 
metal  is  off  the  blowholes ;  then  the  blast  stops,  some 
other  melted  iron  with  just  enough  carbon  in  it  to  make 
the  whole  into  steel  is  poured  in,  the  mouth  then  de- 
scends till  the  whole  batch  of  melted  steel  pours  out  into 
a  huge  "  ladle  "  placed  below,  and  there  we  must  leave  it. 

Now,  when  we  want  to  melt  steel  we  use  dishes  made 
of  graphite  (like  the  "  lead  "  of  pencils).  When  we  want 
a  very  intense  light  we  heat  a  piece  of  lime  till  it  glows 
(but  does  not  burn) ;  and  sand  is  the  principal  thing  in 
the  unmeltable  fire  brick  which  lines  the  converter. 

Yet  we  have  seen  that  even  these  three  things,  so  dif- 
ficult to  melt,  were  vaporized  by  intense  heat,  and  be- 
came a  sheet  of  glowiny  flame. 

What  shall  we  think  of  other  things  about  us  ?  (That 
ever3rthiiig  can  be  turned  into  glowing  gas  or  vapor.) 

18.  In  telling  of  Bessemer  steel  making,  I  used  the 
words  "  when  the  color  of  the  flame  shows  that  little  be- 
sides iron  is  burning."  What  "color"  has  to  do  with  it 
I  can  now  lead  you  to  see.  Here  is  an  alcohol  lamp. 
Having  been  well  washed  and  a  new  piece  of  wick  and 
fresh  alcohol  put  in,  the  flame  is  nearly  colorless.*  In 
these  little  dishes  I  have  five  things  I  want  you  to  see 
the  flame  color  of,  so  in  each  I  will  dip  a  match  stick  or 
splinter  of  dry  wood  to  hold  in  the  alcohol  flame.  We 
will  now  darken  the  room  as  much  as  possible,  that  you 
can  the  better  observe  while  I  hold  one  after  another 
in  the  flame. 

No.  1  solution  is  of  crystals  of  some  pure  potash  salt 
-KClOs  or  KNos. 

No.  2  solution  is  of  strontium  nitrate — Sr(NOs)a. 

*  A  clean  Bunsen  burner  will  be  even  better. 


212  SYSTEMATIC  SCIENCE  TEACHING. 

No.  3  solution  is  of  common  "  bluestone,"  or  copper 
sulphate — CuS04. 

No.  4  solution  is  of  copper  chloride — CuCla. 

No.  5  solution  is  of  common  table  salt  or  soda. 

(Introduce  these  into  the  flame  in  the  order  given  or 
they  may  interfere  with  each  other.) 

No.  1.  What  color  to  flame  ?  (Violet,  of  the  metal 
potassium.) 

No.  2.  What  color  to  flame?    (Crimson,  of  strontium.) 

No.  3.  What  color  to  flame  ?    (Green,  of  copper.) 

No.  4.  What  color  to  flame  ?  (Blue,  of  chlorine  and 
copper.) 

No.  5.  What  color  to  flame  ?     (Yellow,  of  sodium.) 

So  I  might  go  on,  and  by  greater  heat  and  proper  ap- 
paratus get  the  flame  of  every  element  we  know  of,  and 
find  that  each  element  has  a  flame  color  of  its  own. 

19.  Let  us  think  again  of  the  whirling  rod  we  talked 
of  in  the  molecule  lessons  (Step  XXXI,  Lesson  16). 

After  the  separate  blows  became  too  fast  to  distin- 
guish, we  had ?    (Sound.) 

What  did  Count  Rumford  teach  us  ?  (Heat  is  a  mode 
of  molecular  motion.) 

The  blacksmith  ?  (More  frequent  vibrations  gave  red 
light.) 

Now,  if  his  shop  was  dark  and  a  hole  in  the  wall 
opened  into  another  room  (also  dark),  what  might  we  see 
on  the  opposite  wall  ?     (A  spot  of  red  light.) 

In  what  direction  ?  (Straight  through  from  the  red- 
hot  iron.) 

If  this  glass  prism  (whose  cross  section  is  like  the 
grain  field  the  soldiers  marched  through)  were  placed  by 

the  hole  so  that  the  light  had  to  pass  through ?    (The 

spot  would  cliange  to  one  side.    IT  11.) 

Would  it  still  be  red  f    (Yes.) 

If  the  vibrations  increased  the  red  would  become ? 

(Orange.) 


WHAT  THE  TELESCOPE  REVEALS.  213 

Yes;  stin  the  orange  spot  would  not  be  where  the 
red  was,  but  a  little  farther  away  from  the  straight 
line. 

Next  would  come ?    (Yellow.) 

This  would  be  still  more  bent. 

What  other  color  would  follow  ?     (White.) 

Each  of  which  would  in  succession  creep  farther  and 
farther  away  from  the  spot  made  before  the  prism  was 
put  in  the  way. 

Which  light  has  the  slowest  vibrations  ?     (Red.) 

Which  the  most  rapid  ?     (Violet.) 

Are  these  vibrations  equally  changed  by  a  prism  ? 
(No.) 

Which  are  bent  most  ?    (The  most  rapidly  recurring.) 

The  least  ?    (Slowest.) 

If  these  colors  were  all  united  in  one  beam  how 
could  we  separate  (disperse)  them  again  ?  (Pass  the 
light  through  a  prism.) 

What  color  would  be  bent  least  ?     (Red.) 

Give  the  order  of  the  remaining  colors.  (Orange, 
yellow,  green,  blue,  violet.) 

What  colors  did  I  show  you  in  the  flame  ?  (Red,  yel- 
low, green,  blue,  and  violet.) 

How  would  these  colors  be  bent  (refracted)  by  the 
prism  ?    (Each  one  differently.) 

Suppose  I  put  all  in  the  flame  at  once  ?  (The  more 
intense  colors  would  cover  up  or  hide  the  weaker.) 

But  would  all  the  colors  be  in  the  flame  ?  (Yes,  must 
be  there,  only  can  not  be  distinguished.) 

Can  you  think  of  any  way  to  separate  them  so  that 
each  can  be  seen  ?     (By  a  prism.) 

Is  it  not  wonderful !  If  all  the  colors  mixed  in  one 
ray  pass  through  a  prism,  each  color  is  differently  bent, 
and  will  be  separated  in  the  colored  spectrum. 

20.  A  single  lens  or  prism  is  only  able  to  spread 
out  the  light  a  little,  so  several  prisms  are  arranged, 


214  SYSTEMATIC  SCIENCE  TEACHING. 

one  after  another,  in  an  instrument  called  the  spectro- 
scope.* 

With  this  the  colors  are  widely  separated  into  a  long 
band,  where  they  can  be  examined. 

If  we  turned  a  spectroscope  on  our  mixed  flame  what 
would  it  show  ?     (Each  color  by  itself.) 

And  we  could  thus  tell ?    (What  substances  were 

bumingO 

21.  Having"  learned  that  each  color  is  differently  bent 
in  passing  obliquely  from  one  medium  into  another,  and 
can  thus  be  separated  by  the  prisms  of  a  spectroscope,  let 
us  notice  something  wonderful  about  common  white 
light,  as  we  call  that  which  is  not  colored. 

Who  has  ever  seen  a  colored  band  of  light  ?  Where  ? 
(On  tablecloth  or  wall.) 

Was  the  sunshine  in  the  room  ?  (Yes,  and  it  must 
have  passed  through  the  prismlike  corner  of  something 
made  of  glass,  which  not  only  turned  the  ray  but  spread 
it  out  like  a  colored  fan.) 

What  kind  of  light  was  it  that  entered  the  glass  ? 
(White.) 

And  it  came  out ?    (A  colored  band.) 

When  do  we  see  a  rainbow?  (When  we  look  at  the 
reflection  of  the  sun  shining  on  falling  rain.) 

Of  what  shape  are  falling  drops  ?     (Spherical.) 

Where  is  a  sphere  thickest  ?  (In  the  middle,  like  a 
lens.) 

What  light  is  it  that  enters  these  little  raindrop 
lenses  ?     (Sunlight.) 

And  what  happens  to  this  white  sunlight  ?     (Its  rays 
are  bent  and  separated  by  the  drops  till  we  see  the  beau- ' 
tif  ul  band  of  colors  called  a  rainbow.) 

Other  examples  are  seen  in  broken  glass  or  ice,  films 
of  oil  on  water,  soap  bubbles,  etc. 

*  Lockyer's  Astronomy,  chap.  xv. 


WHAT  THE  TELESCOPE  REVEALS.  215 

What,  then,  must  we  conclude  about  white  light  ? 
White  light  is  composed  of  all  the  colors  united  and 
condensed. 

22.  How  were  the  colors  arranged  in  the  rainbow,  or 
the  colored  light  on  the  table  or  wall  ?  (A  continuous 
band.) 

If  you  could  see  the  spectrum  of  gases  you  would  no- 
tice a  difference. 

(Show  in  some  book,*  or  have  drawn  on  the  board.) 

What  is  it?  (Burning  gases  have  bright  lines  of 
color.) 

Yes.  That  of  sodium  is  in  how  many  ?  (One  yellow 
line.) 

How  would  you  know  burning  hydrogen  gas  ?  (One 
orange  and  two  blue  lines.) 

And  oxygen  ?     (Many  lines.) 

Students  have  found  that  these  lines  are  always  the 
same  in  position  and  color. 

Remembering  now  that  glowing  solids  (sun,  hot  iron, 
etc.)  give  continuous  spectra,  while  glowing  gases  give 
spectra  with  bright  lines,  let  us  turn  the  spectroscope  on 
the  steel-converter  flame. 

What  shall  we  see  ?  (The  bright  lines  of  burning 
iron,  lime,  sand,  oxygen,  and  other  gases  and  vapors.) 

If  we  looked  at  the  melted  steel  as  it  was  poured  out  ? 
(The  continuous  spectrum  of  a  hot  liquid.) 

At  a  bar  of  hot  steel  in  the  rolling  mill  ?  (Continu- 
ous spectrum  of  a  solid.) 

We  thus  see  two  classes  of  spectra,  and  say  spectra 
may  be  "continuous"  or  "bright-lined." 

23.  We  have  learned  that  flames  can  only  come  from 
burning  gas  or  vapor.  That  each  substance  has  its  own 
bright  lines  of  color  in  these  flames  which  are  differently 
bent  (refracted)  by  the  prisms  of  the  spectroscope,  thus 

*  Magic  Glasses  or  Lockyer. 


216  SYSTEMATIC  SCIENCE  TEACHING. 

enabling  us  to  tell  whether  a  light  we  may  see  comes  from 
a  glowing  white-hot  solid  or  from  burning  gases  or  va- 
pors, and  also  what  is  burning  in  them. 

That  all  substances  we  know  of  can  be  vaporized  and 
give  the  bright-line  spectra.  That  when  heated  suf- 
ciently  in  the  liquid  or  solid  form,  all  these  substances 
give  white  light,  whose  spectrum  or  band  of  color  is  un- 
crossed by  dark  lines. 

Now,  as  Laplace  studied  the  planets  and  moons  of 
our  system  and  in  connection  thought  on  the  then  recent 
discoveries  of  Herschel,  the  idea  grew  in  his  mind  that 
the  sun  and  all  his  attendant  planets  may  once  have  been 
a  nebula— a.  great  cloud  of  glowing  gas. 

In  what  state  would  all  the  sand,  iron,  carbon,  lime 
lead,  gold,  etc.,  be  ?    (In  a  brightly  glowing  gas.) 

How  large  was  this  cloud  of  intensely  heated  gas  and 
vapor  ?  (It  must  have  extended  far  beyond  the  most 
remote  planet — Neptune.) 

Is  space,  the  region  off  into  which  we  look  to  see  the 
sun  or  stars,  hot,  or  cold  ?    (Cold.) 

Then    this     nebulous    cloud    would    gradually ? 

(Cool.) 

As  it  cooled,  it  would,  as  other  things  do ?    (Grow 

smaller.) 

In  some  unexplained  way  Laplace  thought  this  con- 
tracting gas  began  to  revolve. 

This  would  make  the  outer  portions  try  to  do  what  ? 
(Fly  off.) 

Yes ;  but  gas  could  hardly  take  the  form  of  a  drop, 
so  it  was  supposed  a  ring  separated  and  went  on  revolv- 
ing. As  the  remaining  portion  contracted  more  and 
more  a  second  ring  was  given  off  and  left  behind,  then 
a  third,  and  so  on  till  at  least  eight  principal  portions 
had  separated. 

Now  let  us  go  back  to  the  first  ring.  Left  behind, 
this  would  cool  more  rapidly,  till  at  last  it  is  supposed 


WHAT  THE  TELESCOPE  REVEALS.  217 

the  ring:  broke  and  gathered  into  a  hall,  and  as  the  ring 
broke  this  baU  acquired  a  revolving  motion  on  its  own 
axis. 

This  revolution  in  time  caused  a  portion  to  separate 
from  the  ball,  and  this,  the  theory  claims,  originated 
what  ?     (Neptune  and  his  one  moon.) 

What  came  from  the  second  ring  ?  (Uranus  and  six 
moons.) 

From  the  third  ring  ?  (Saturn,  his  eight  moons,  and 
several  rings.) 

From  the  fourth  ring  came ?    (Huge  Jupiter  and 

his  five  moons.) 

From  the  fifth  ?    (Mars,  with  two  moons.) 

From  the  sixth  ring  ?    (Our  earth.) 

And  as  this  huge  globe  of  heated  matter  cooled  and 
contracted,  what  at  last  separated  ?    (Our  moon.) 

From  the  seventh  portion  originated ?    (Venus.) 

And  the  eighth  ?    (Mercury.) 

What  name  do  we  give  the  portion  now  left  ?    (Sun.) 

These  are  some  of  the  points  in  Laplace's  brilliant 
conception  of  how  our  solar  system  came  to  be. 

24.  Some  Proofs. — Here  are  some  shot  for  each  of  you. 

How  do  you  imagine  so  many  very  round  pieces  of 
lead  are  made  ?  (The  lead  is  taken  to  the  top  of  a  very 
high  tower,  melted,  and  allowed  to  drop  through  a  kind 
of  sieve  into  a  tank  of  water  at  the  bottom  of  the  tower.) 

Let  us  think  of  this  very  carefully. 

As  the  lead  leaves  the  sieve  it  is  in  what  state  ? 
(Melted.) 

What  does  it  rest  on  ?    (Nothing.) 

Are  the  molecules  in  a  liquid  free  to  arrange  them- 
selves ?     (Yes.) 

How  will  they  do  this  in  an  unsupported  drop  of 
liquid  f  (Will  attract  each  other  and  gather  about  the 
center,  forming  a  sphere.) 

If  such  a  sphere  of  liquid  were  made  to  spin  on  its 


218  SYSTEMATIC  SCIENCE  TEACHING. 

axis ?    (Would  bulge  at  the  equator  aud  flatten  at 

the  poles.) 

Do  we  know  of  any  such  rotating  spheres  ?  (Sun, 
earth,  some,  and  probably  all,  the  planets.) 

Are  they  bulged  and  flattened  ?  (Our  earth  and  some 
of  the  other  "  members  of  the  family  "  certainly  are.) 

But  the  earth  is  not  "  liquid  "  ?  (No ;  but  its  rocks 
and  heated  interior  plainly  teach  it  once  was.) 

If  Laplace  were  correct,  what  should  we  expect  the 
remaining  portion  of  the  nebula  to  be  like  ?  (A  huge, 
hot,  revolving  sphere.) 

Just  what  our  sun  is. 

What,  then,  are  some  of  the  proofs  Laplace  had  ? 
(A  hot,  central  sun,  surrounded  by  planets  and  their 
moons,  all  bearing  in  shape  and  motions  unmistakable 
marks  of  their  common  and  fiery  origin.) 

25.  Now  let  us  use  what  we  have  learned  by  fi:xing 
our  spectroscope  on  the  end  of  our  telescope. 

Here  is  a  colored  chart  of  the  spectrum  of  the  sun* 

Is  it  a  continuous,  or  bright-line,  spectrum  ?  (Con- 
tinuous, with  dark  lines.) 

I  can  only  tell  you  now  that  by  these  dark  lines  we 
have  learned  to  tell  what  is  burning  in  the  great  sun, 
93,000,000  of  miles  away. 

What  would  be  the  spectrum  of  the  moon  f  (Same 
as  sun.) 

Stars  also  have  a  spectrum.  Here  is  a  chart  of  one 
(Aldebaran)  much  like  the  sun. 

If  we  could  gather,  with  a  large  lens  or  reflector,  as 
much  light  as  possible  from  the  star  cluster  in  Androm- 
eda, and  observe  the  spectrum  ?  (Still  continuous,  like 
the  sun,  and  bright  stars.) 

How  will  a  real  nebula  look  ?  (Bright-line  spec- 
trum.) 

*  Magic  Glasses,  p.  127. 


WHAT  THE  TELESCOPE  REVEALS.  219 

Are  the  real  nebulae  solid,  liquid,  or  gaseous  ?  (Burn- 
ing gases.) 

Laplace  only  guessed  this  to  be  so.  Now  it  is  proved 
by  the  spectroscope,  and  adds  much  strength  to  his 
theory  of  the  solar  and  other  systems. 

Here  we  must  leave  this  interesting  subject.  I  trust 
it  has  given  you  new  and  correct  ideas  of  light,  and  of  the 
useful  instruments  which  aid  us  in  our  star  studies.  It 
has  also  added  one  more  chapter  in  the  wonderful  his- 
tory of  this  earth,  which  you  will  find  more  and  more 
interesting  as  you  study  about  lier. 

26.  Constellations. — For  this  step  find  those  connected 
with  the  story  of  Perseus,*  which  can  be  well  found  at 
this  season  (see  Lockyer,  p.  191,  "  October  16,  8.30  P.  M.," 
or  *'  November  7,  9  P.  M.,"  or  Serviss,  chapter  iii).  This 
brave  son  of  Jupiter  having  received  the  shield  of  wis- 
dom (Minerva)  and  the  sword  and  winged  sandals  of  Mer- 
cury, secured  the  "hat  of  darkness"  from  Pluto,  and, 
thus  armed  and  invisible,  slew  the  terrible  Medusa. 
From  her  blood  sprang  the  winged  horse  PegasuB.  Re- 
turning home  with  the  Medusa's  head,  he  spies  beautiful 
Andromeda  chained  by  the  sea,  turns  Cetus,  the  sea  mon- 
ster coming  to  devour  her,  into  a  rock  by  showing  the 
Medusa's  head,  and  gains  the  permission  of  Cepheus  and 
Cassiopeia  (father  and  mother  of  the  maid)  to  marry 
their  daughter. 

Kead  this  with  or  to  the  class,  and  in  connection  make 
star  charts,  as  before,  of  the  constellations. 

In  finding  the  groups,  proceed  as  follows  : 

1.  Review  the  Great  Bear  (dipper). 

2.  Follow  the  straight  line  from  the  "  pointers  "  to  the 
north  star  and  on  beyond  till  a  square  of  four  bright  stars 
is  found.     These  mark  the  winged  horse  Pegasus. 

3.  The  northeast  one  of  this  "  square  of  Pegasus "  is 

*  Bulfinch,  pp.  139-154,  Greek  Heroes,  and  Burritt. 


220  SYSTEMATIC  SCIENCE  TEACHING. 

also  in  the  cheek  of  fair  Andromeda.  Now  start  from  the 
diagonally  opposite  corner  star  of  the  square  and  follow 
the  line  through  the  star  in  the  cheek  to  two  others  in 
her  girdle  and  foot.     These  three  will  mark  the  group. 

4.  Follow  the  line  through  the  star  in  the  foot  till  it 
crosses  the  Milky  Way,  in  which,  nearly  at  an  angle  of 
45°  to  that  direction,  lie  three  bright  stars,  marking  the 
constellation  of  Perseus, 

5.  To  one  side  (south)  of  the  space  between  the  mid- 
dle and  last  stars  of  Perseus  is  a  group  of  five  stars  (four 
rather  faint)  forming  the  Medusa's  Head,  which  Perseus 
carries  in  his  hand. 

6.  In  the  same  direction  will  be  seen  the  bright  pair 
of  stars  in  the  Eam's  Head,  and  beyond  these  lies  Cetns, 
the  sea  monster.  A  line  from  the  north  star  between  the 
two  upper  stars  in  Perseus  and  through  the  bright  star 
in  the  Medusa's  Head  will  pass  near  the  brightest  star  in 
Cetus.  Then  find  the  irregular  circle  of  seven  stars  about 
the  one  in  the  eye. 

7.  Eeturning  to  Perseus,  next  him  find  Cassiopeia  (the 
chair  or  "  W  "),  which  we  have  before  used  to  find  the 
star  cluster  and  nebula  (Buckley's  Magic  Glasses,  chap- 
ter vii). 

8.  Beyond  Cassiopeia,  and  between  her  and  the  Swan, 
is  Cepheua  Three  stars  of  medium  brightness,  lying 
along  the  Milky  Way  on  the  side  nearest  the  north  star 
mark  this  group. 

Suggestions  as  to  star  lanterns,  places  of  meeting,  etc., 
will  be  found  in  Step  XXX. 

The  Review  of  this  step  will,  as  usual,  be  placed  at 
the  beginning  of  the  next,  but  can  also  be  used  here  with 
profit,  although  such  work  as  I  have  outlined  does  not 
need  the  uninteresting  retracing  of  steps  implied  in  the 
term  review.  Being  largely  a  matter  of  the  child's  per- 
sonal observation  and  experience,  it  will  never  be  for- 
gotten, and  the  only  fitting  supplement  to  such  work  is 


WHAT  THE  TELESCOPE  REVEALS.  221 

to  use  the  present  acquirements  as  keys  to  new  and  great- 
er knowledge.  Only  be  sure  the  impressions  are  correct^ 
and  then  press  on  wherever  the  way  opens. 

The  next  step  in  this  subject  is  XLII — The  Earth's 
Early  History. 


STEP  XXXVI.— CRYSTALS  AND  CRYSTALLIZATION. 

Object  of  these  lessons : 

1.  To  review  surface  and  solid  forms.  (Steps  XXI  and 
XXVI.) 

2.  To  prepare  for  minerals.     (Step  XXXVII.) 

3.  To  prepare  for  soil  and  rock  making.  (Steps  XLIV 
and  XL VIII.) 

Time  needed.— About  twenty  lessons  of  thirty  min- 
utes each. 

Material  for  class  of  thirty  : 

30  clay  boards  and  molding  clay,  of  Step  XXVI. 

30  magnets,  of  Step  III. 

Box  of  toothpicks  or  wires. 

2  pounds  each  of  alum,  copper  sulphate,  and  iron 
filings. 

Fragments  of  glass,  crystalline  calcite,  rock  salt,  and 
galena. 

60  glass  sauce  dishes.     (Do  not  use  porcelain.) 

Set  of  crystal  models. 

Expense.— Almost  nothing.  Many  of  the  things  are 
already  in  stock,  and  the  rest  can  be  gathered,  brought 
by  the  pupils,  or  cheaply  bought.  Good  crystal  models 
are,  however,  expensive,  but  can  be  dispensed  with,  ex- 
cept those  made  in  the  solid  form,  Step  XXVI,  or  by  the 
following  directions : 

Have  some  skilled  carpenter  get  out  four  rods  of  ap- 
ple, cherry,  black  walnut,  or  other  fine-grained  and  well- 
seasoned  wood,  and  cut  them  into  blocks  according  to 
222 


CRYSTALS  AND  CRYSTALLIZATION.  223 

the  directions  in  the  table  on  pages  224  and  225  (dimen- 
sions are  in  inches  and  fractions  of  an  inch). 

Cut  thirty  of  each.  The  pupils  can  sandpaper  the 
ragged  edges.  The  cost  should  not  be  over  two  dollars, 
and  a  valuable  lot  of  material  will  be  secured.  A  bright 
carpenter  might  make  some  pyramids,  etc.  (see  Step 
XXVI),  if  models  were  supplied. 

Preparation  of  Teacher.— Ruskin's  Ethics  of  the  Dust, 
Dana's  Manual  of  Mineralogy,  Tenney's  old  but  helpful 
Geology,  and  Crosby's  Common  Minerals  and  Rocks 
have  been  my  best  aids  in  the  way  of  books,  but  doubt- 
less other  and  more  recent  works  are  to  be  found.  The 
remainder  of  my  study  has  been  with  the  crystals  and 
experiments. 

I  would  advise  the  teacher  who  is  to  give  these  lessons 
to  rely  mainly  on  the  latter,  and  only  use  books  as  need 
may  arise.  Gather  your  material  and  all  the  crystals 
you  can  find.  Then  go  through  the  following  lessons 
and  verify  each  point,  modifying  such  as  your  material 
and  surroundings  may  require.  Then  give  the  lessons, 
and  "practice  will  make  perfect.''  A  review  of  Step 
XXXI,  on  molecules,  may  aid. 

The  Lessons. 

1.  Show  (and  converse  about)  all  the  crystals  you  and 
your  pupils  can  bring  together.  An  interest  will  thus 
arise. 

2.  Give  Linnaeus's  statement :  "Minerals  grow,  plants 
grow  and  breathe,  animals  grow,  breathe,  and  move." 
Such  fixed  limitations  do  not  actually  exist,  but  this  will 
introduce  the  subject,  and  the  exceptions  will  appear  in 
the  proper  place  and  time.  Bring  the  class  to  some  sense 
of  the  fact  that  most  kinds  of  mineral  matter,  although 
seemingly  dead,  always  have  a  particular  way  in  which 
the  molecules  come  together  when  free  to  move.  This 
particular  form  may  undergo  numberless  modifications 


224  SYSTEMATIC  SCIENCE  TEACHING. 


Cross  Section  and  Dimensions 
OF  Rod. 

Length  of  rod  needed. 

Length  of 

blocks  to 

cut. 

r 

1  inch. 

I           I  in. 

120  inches  of  No.  1." 

2  inches. 

1  in. 

^ 

i  inch. 

2  inches 

i  in. 

2 

'/,  in. 

\ 

130  inches  of  No.  2.- 

2  inches. 

i  in. 

170° 

i  inch. 

\ 

3 

V 

95  inches  of  No.  3.  - 

1  inch. 

\llO» 

\ 

'^ 

1|  inch. 

/ 

%  in.          > 

1  inch. 

/l20° 

4 

) 

100  inches  of  No.  4. . 

2  inches. 

CRYSTALS  AND  CRYSTALLIZATION. 


225 


Angle  of  cross  cut. 

Shai)e  of  form  made. 

System  of  crys- 
tallograpb. 

Square  across 

Cube 

Monometrie. 

Right  prism  (long) 

Dimetric. 

M                       « 

"       (short).... 

Dimetric. 

i(                       i( 

Rectangular  prism  . . . 

Trimetric. 

Square  across,  but  on 
20°  slant. 

Oblique  prism 

Monoclinic. 

•  Square  across 

Rhombic  prism 

Trimetric. 

20°  slant,  both  across 
and  down. 

Rhombohedron 

Hexagonal. 

20°  slant,  both  across 
and  down. 

Doubly  oblique  prism. 

Triclinic. 

Square  across 

Short  hexagonal  prism. 

Hexagonal. 

Square  across 

Long  hexagonal  prism. 

Hexagonal. 

16 


226  SYSTEMATIC  SCIENCE  TEACHING. 

by  the  cutting  off  of  corners  and  beveling  of  edges,  but 
through  all  it  remains  true  to  its  own  system,  and  certain 
angles  will  remain  constant  even  to  seconds  of  a  degree. 
Read  parts  of  Ruskin  to  the  class  (Pyramid  Builders). 
Through  all  the  exquisite  forms  of  the  snowflake,  the 
feathery  hoarfrost,  the  solid  ice,  or  the  delicate  tracery 
on  the  window  pane,  runs  an  exactness  and  symmetry 
which  is  awe-inspiring.  They  crowd  and  jostle  each 
other  out  of  all  semblance  to  the  typical  hexagonal  form, 
but  let  even  a  corner  have  the  freedom  to  grow,  and  it  is 
rigidly  true  to  its  system.  When,  as  frequently  in  a  dry 
snow,  the  molecules  of  watery  vapor  floating  in  the  air 
succeed  in  escaping  interference,  a  beautiful  six-pointed 
star  results,  with  the  three  lines  joining  the  six  points 
of  equal  length,  and  forming  an  exact  angle  of  sixty  de- 
grees with  each  other. ' 

3.  Some  hint  of  how  this  happens  can  be  given  in  the 
following  experiment : 

Give  each  pupil  half  a  teaspoonful  of  fine  iron  filings 
and  a  bar  magnet. 

(a)  Remove  the  magnet  well  away  and  drop  the  filings 
over  sheets  of  paper.  We  can  suppose  these  like  the 
molecules  of  an  uncrystalline  substance. 

(b)  Remove  the  filings  and  lay  the  paper  over  the  mag- 
net. Now  sprinkle  the  filings  over  the  paper  again  and 
see  what  beautiful  curves  are  formed.  Each  particle  of 
iron  now  swings  into  its  proper  position,  and  order  takes 
the  place  of  chaos. 

In  some  such  way  must  the  molecules  and  atoms  be 
guided  to  their  places. 

That  they  may  arrange  themselves,  it  is  evident  they 
must  be  free  to  move.  Let  the  class  tell  what  conditions 
of  matter  will  permit  this.  (Vapor,  as  seen  in  the  case 
of  snow  and  sulphur ;  liquid,  as  in  melted  iron  and  wa- 
ter ;  or  in  solutions,  as  salt,  alum,  and  copper  sulphate.) 

4.  What  kinds  of  molecules  will  thus  unite  ? 


CRYSTALS  AND  CRYSTALLIZATION.  227 

Let  us  try  some  experiments  before  we  answer  this. 

Here  are  two  bottles  (fruit  jars)  with  hot  solutions  of 
alum  and  copper  sulphate.  I  put  pure  rain  water  on  the 
substance  several  days  ago,  and  have  frequently  stirred 
the  water.  As  some  of  the  substance  is  still  undis- 
solved, I  know  the  solution  is  saturated  (has  all  it  can 
hold). 

Every  crack  and  crevice  between  the  water  molecules 
is  full  of  molecules  of  alum  or  copper  sulphate. 

Are  these  molecules  free  to  move  ?    (Yes.) 

Why  did  I  heat  the  water  ?  (So  that  it  could  hold 
more  of  the  mineral  in  solution.) 

Even  these  enlarged  spaces,  then,  are  full. 

What  will  happen  when  the  water  cools  ?  (Its  mole- 
cules will  draw  closer  together  and  some  of  the  mineral 
be  forced  out.) 

And  I  shall  find  a  lot  of  molecule  dust  on  the  bot- 
tom ?    (No  ;  cohesion  will  make  solid  masses  of  them.) 

Being  free  to  move,  these  molecules  will  arrange 
themselves  in  certain  ways,  and  these  "masses"  will 
be ?    (Crystals.) 

After  the  cooling  has  excluded  all  the  mineral  it  can, 
how  shall  I  compel  the  water  to  deposit  still  more  ? 
(Dry  it  away.) 

Let  us  test  these  conclusions.  Here  are  sixty  warm 
glass  dishes  and  sixty  pieces  of  cardboard  large  enougli 
to  cover  them.  Each  take  two  pieces  of  cardboard  and 
write  your  name  plainly  on  them.  Now  each  take  two 
dishes,  and  after  wiping  free  from  dust  place  one  on  this 
table  near  the  register  (or  any  safe  place  where  they  will 
cool  slowly).  I  will  then  fill  it  1  cm.  deep  with  alum  so- 
lution. Cover  it  with  one  card,  and  on  the  card  place 
the  other  clean  and  warm  dish  for  me  to  fill  as  before 
with  the  copper-sulphate  solution.  Place  the  second  card 
on  this  dish.  Now  we  will  cover  all  with  a  cloth  to  keep 
out  the  dust. 


228  SYSTEMATIC  SCIENCE  TEACHING. 

I  have  warmed  the  dishes  and  put  all  in  this  warm 
place,  where  the  temperature  will  slowly  fall,  till  morn- 
ing", when  we  will  see  if  cooling  does  make  hot  solutions 
deposit  mineral  matter. 

In  the  morning  examine  the  dishes  and  see  the  crys- 
tals which  will  have  formed.  To  test  the  effect  of  evapo- 
ration, place  the  dishes  where  there  will  be  a  free  circula- 
tion of  warm  air  (carefully  exclude  dust),  and  leave  till 
the  water  is  nearly  dried  away.  Let  the  pupils  now  keep 
two  or  three  of  the  best  crystals,  and  return  the  rest  of  the 
liquid  and  imperfect  crystals  to  the  proper  jars  of  solu- 
tion. 

5.  Do  hot  solutions  of  mineral  deposit  crystals  in 
cooling  ? 

Does  evaporation  cause  the  same  deposit  ? 

What  will  control  the  size  of  the  crystals  ?  (Slow 
cooling  or  evaporation  will  cause  large  crystals.) 

Then  a  crystal  needs  time  to  grow  as  well  as  anything 
else. 

If,  then,  I  find  large  crystals ?    (They  were  long 

in  growing.) 

If  small  ones  ?     (They  formed  quickly.) 

If  perfect  in  shape  f  (Were  free  from  the  crowding 
of  others.) 

Yes,  and  you  can  much  improve  such  crystals  as  those 
made  by  keeping  two'or  three  free  from  the  others  and 
turning  them  over  frequently. 

Why  do  I  say  "  turn  over "  ?  (IVIolecules  can  not 
freely  get  at  the  underside  as  it  rests  on  the  dish.) 

Each  may  now  clean  one  dish  for  a  most  remarkable 
and  instructive  experiment.  See.  I  am  going  to  mix  the 
white-alum  solution  with  the  blue-copper  sulphate.  I 
will  pour  a  double  quantity  in  each  dish  in  order  that  we 
may  see  the  influence  time  has,  and,  being  careful  to 
keep  out  dust,  leave  till  evaporated  three  fourths. 

6.  While  waiting  for  this  evaporation  review  the  class 


CRYSTALS  AND  CRYSTALLIZATION.  229 

on  the  plane  figures  and  solid  form  of  Steps  XXI  and 
XXVI.  This  will  be  time  well  spent  if  a  thorough  fa- 
miliarity is  gained  of  the  various  angles,  triangles,  quad- 
rilaterals, etc.,  and  the  solids  which  they  may  inclose. 

7.  When  three  fourths  of  the  water  is  evaporated  from 
the  mixed  solution  remove  the  cake  of  crystals  in  each 
dish,  dip  it  quickly  into  some  ice-cold  water  to  rinse  off 
the  surface,  and  then  place  on  papers  to  dry. 

What  remarkable  thing  has  happened  ?  (A  perfect 
separation  of  the  crystals,  alum  and  bluestone  standing 
side  by  side,  or  even  on  each  other,  and  still  pure.) 

So  certain  are  crystals  to  be  pure,  that  when  gi'eat 
purity  is  needed,  as  in  some  chemicals,  it  is  secured  by 
crystallizing  the  substance,  washing,  and  recrystallizing 
again,  if  need  be. 

Were  the  molecules  of  the  two  substances  thoroughly 
mixed  ?    (Yes.) 

How  did  they  come  to  separate  ?  (Similar  molecules 
attracted  each  other.) 

Is  it  not  wonderful  that  they  never  make  a  mistake 
either  as  to  what  molecules  to  join  nor  the  form  the  crys- 
tal is  to  take  ? 

Would  the  same  thing  probably  happen  to  mixed  va- 
pors f    (Yes.) 

How  about  melting  things  together  like  iron  and 
lead  ?     (Also  separate.) 

If  I  could  melt  several  different  kinds  of  minerals 
together  or  have  them  in  the  same  solution,  do  you  sup- 
pose they  would  also  separate  ?  We  shall  see,  some  day, 
how  important  this  is. 

To-morrow  we  will  further  illustrate  this,  if  it  is  very 
cold. 

Who  will  bring  about  a  litre  of  strong  salt  and  water 
and  a  bowl  ?     (Mary.) 

Who  will  bring  about  a  litre  of  coffee  water  and  a 
bowl  to  hold  it  ?    (Kate.) 


230  SYSTEMATIC  SCIENCE  TEACHING. 

Who  about  a  litre  of  vinegar  and  a  bowl  ?    (John.) 
Who  the  same  volume  of  inky  water  and  a  bowl  ? 
(Samuel.) 

Who  will  bring  a  bowl  to  hold  the  rest  of  this  alum 
solution  ?    (Thomas.) 

Who  a  bowl  for  this  copper  sulphate  ?    (Paul.) 
Samuel,  will  this  inky  water  freeze  pure  f    We  will 
see. 

8.  If  very  cold  on  the  morrow,  put  the  things  called 
for  yesterday  6  to  10  cm.  deep  in  wide-mouthed  bowls 
and  set  them  out  to  freeze.    When  the  ice  on  each  is  5 
to  10  mm.  thick  bring  in  the  bowls  to  a  warm  place,  and 
in  a  few  moments  the  cakes  will  become  loose.    Rinse 
them  off  quickly  in  plenty  of  ice-cold  water,  and  lay  in 
clean  and  labeled  dishes  to  melt.    Now  label  six  clean 
glass  cylinders  (graduates)  and  pour  in  the  waters. 
Are  they  colored  ?    (Not  if  care  has  been  used.) 
To  further  prove  their  purity  try  the  following  tests : 
Dissolve  a  pinch  of  lead  acetate  in  10  c.  c.  of  water  be- 
forehand, and  have  some  ammonia  ready.    In  three  test 
tubes  (or  small  bottles)  have  some  of  the  salt,  alum,  and 
copper  solutions  left  under  the  ice. 

1.  Salt  solution  +  lead  acetate  =  white  curd.  Water 
from  its  ice  -f  same  =  nothing  or  trace. 

2.  Alum  -f  lead  acetate  =  white  curd.  Water  from  its 
ice  -f-  same  =  nothing. 

3.  Copper  solution  +  ammonia  =  blue  color.  Water 
from  its  ice  -f  ammonia  =  nothing. 

The  senses  of  smell  and  taste  can  be  applied  to  the 
others. 

Would  water  from  sea  ice  be  salt  ?    (No.) 

How  does  freezing  spoil  ink  ?  (Separates  the  coloring 
matter  and  water.) 

Cider  is  made  stronger  by  freezing.  How  ?  Vinegar 
can  be  concentrated  by  freezing.  How  ?  (Freeze,  and 
then  draw  off  the  unfrozen  part.) 


CRYSTALS  AND  CRYSTALLIZATION.  231 

Why  are  the  bladelike  crystals  in  frozen  milk  trans- 
parent ?    (The  crystals  are  water.) 

If  sticks  or  weeds  were  floating  in  a  pond  would  the 
ice  be  free  from  them  ?    (No.) 

And  so  we  frequently  find  things  which  the  crystals 
could  not  exclude,  and  so  grew  around.  Sometimes  these 
were  even  such  strange  things  as  drops  of  water  or  por- 
tions of  a  gas  or  vapor.  These  must  have  been  entrapped 
in  some  corner,  and,  unable  to  escape,  were  inclosed. 

(Show  here,  if  possible,  crystals  inclosing  drops  of 
water,  crystals  of  other  materials,  etc.) 

If  we  find  needlelike  or  perfect  crystals  surrounded 
by  a  mass  of  imperfect,  crowded  crystals  (show  quartz 
with  included  rutile,  etc. ;  calcite  with  copper,  silver, 
etc.,  or  crystals  of  tourmaline  running  through  rocks), 
which  must  have  formed  first  f  (The  perfect  or  inclosed 
crystals.) 

Why  ?  (Could  not  have  penetrated  or  taken  perfect 
shape  after  the  others  were  a  solid  mass.) 

Look  at  the  cake  of  separated  crystals  and  see  which 
seem  to  have  formed  first.     (Alum.) 

How  do  you  know  ?    (Copper  sulphate  is  on  them.) 

Here  is  a  rock  with  large  crystals  of  mica  among 
glassy  quartz  and  shiny  feldspar  :  Which  must  have 
formed  first  ?     (Mica.) 

What,  then,  have  we  learned  about  crystals  to-day  ? 

1.  Mixed  substances  may  separate  in  crystallizing. 

2.  Some  things  crystallize  sooner  than  others. 

3.  Those  crystallizing  first  are  the  most  perfect  and 
largest. 

4.  The  other  substances  are  crowded  around  or  on 
these,  and  hence  less  perfect  in  shape. 

9.  Forms  of  crystals  will  now  be  considered. 

Explain  to  the  class  what  is  meant  by  the  axes  of  a 
crystal.  That  to  talk  of  crystals,  of  their  faces  and  an- 
gles, it  is  necessary  to  imagine  lines  through  the  solid 


232  SYSTEMATIC  SCIENCE  TEACHING. 

crystal,  measuring  the  dimensions  of  length,  breadth, 
and  thickness,  and  about  which  the.  various  plain  sur- 
faces are  arranged.    (See  Step  XXVI.) 

Emphasize  the  fact  that  all  axes  must  meet  in  the 
center  of  the  crystal.  A  cube  will  help  in  explaining 
this. 

10.  Explain  principal  and  secondary  planes  of  sym- 
metry. (See  Elements  of  Crystallography,  Williams, 
pp.  32-34  and  44,  45.) 

11.  Next  give  each  three  50-mm.  (2-inch)  sticks  or 
wires  (such  as  used  in  the  kindergarten  for  "  pease- work  ") 
and  a  little  clay. 

Make  a  clay  ball  the  size  of  a  small  marble  and  thrust 
three  of  the  egwaZ-lengthed  wires  through  it  to  represent 
the  three  axes  of  the  cube. 

Be  sure  all  the  angles  the  wires  make  with  each  other 
are  right  angles.  Now  compare  the  solid  cube  and  this 
skeleton. 

What  angles  do  all  the  axes  make  with  each  other  f 
(Right.) 

What  is  the  length  of  the  axes  ?    (All  equal.) 

What  angles  do  the  faces  make  with  the  axes  ? 
(Right.) 

What  angles  do  the  faces  make  with  each  other  ? 
(Right.) 

What  shape  are  all  the  faces  ?    (Square.) 

What  kind  of  solid  angles  ?    (Square  corners.) 

If  a  cubic  crystal  were  crowded  among  others  might 
it  be  forced  to  become  unsymmetrical  ?    (Yes.) 

Here  are  some  small  fragments  of  rock  salt  (or  of  ga- 
lena) which  is  cubical  in  crystallization,  but  crowded  in 
great  masses.  Break  (cleave)  it  in  several  pieces  by  gen- 
tle taps  and  then  examine  the  solid  corners.  Some  of 
the  pieces  are  oblong  and  otherwise  differ  from  cubes,  but 
how  does  the  look  (luster)  of  the  three  surfaces  about 
the  solid  angle  compare  ?    (Is  the  same.) 


CRYSTALS  AND  CRYSTALLIZATION.  233 

Now  do  not  forget  this,  for  it  is  important.  At  the 
close  of  these  lessons  I  shall  ask  each  one  to  have  a  col- 
lection of  the  specimens  I  give  or  you  may  get  or  make 
to  illustrate  the  subject,  so  each  have  a  neat  skele- 
ton cube,  and  keep  the  fragments  of  a  cubic  mineral 
with  it. 

Of  what  length  are  the  axes  ?     (Equal.) 

So  this  system  of  crystals  is  called  the  "  monometric  " 
(one  measure),  for  all  the  crystals  have  the  three  axes  of 
equal  length,  and  at  right  angles  with  each  other.* 

12.  Yesterday  we  learned  about  the  first  system  of 
crystals,  called  the ?    (Monometric.) 

Why  ?    (All  its  three  axes  are  equal  in  length.) 

What  luster  did  the  three  surfaces  about  the  solid  an- 
gles have  ?    (The  same.) 

Did  the  crystal  seem  to  cleave  with  equal  ease  in  all 
three  directions  ?     (Yes.) 

The  second  system  is  called  the  "dimetric."  It  has 
other  names,  but  this  is  best  here. 

What  does  dimetric  mean  ?    (Two-measure.) 

Exactly.  Now  take  two  sticks,  and,  leaving  one  full 
length,  cut  the  other  exactly  in  two.  Make  a  clay  ball, 
and  arrange  the  three  axes  the  same  as  in  the  cube. 

The  dimetric  system  of  crystals,  then,  has  how  many 
axes?     (Three.) 

At  what  angle  with  each  other  ?    (Right.) 

Of  what  length  ?   (Two  equal,  and  the  vertical  longer.) 

Or  shorter  would  still  give  us  two  measures. 

Compare  it  with  this  square  prism. 

Do  they  agree  ?    (Yes.) 

One  after  another  tell  me  some  of  the  things  about 
our  skeleton  and  this  prism. 

(Stands  erect  on  a  square  base  ;  all  angles  of  axes  or 

*  I  have  retained  the  old  terms  mono-,  di-,  trimetric,  because 
descriptive  in  terms  often  used  in  the  other  sciences. 


234  SYSTEMATIC  SCIENCE  TEACHING. 

of  meeting  planes,  right  angles ;  solid  corners,  "  square 
corners  "  ;  side-  (lateral-)  faces  rectangles.) 

Would  all  this  be  equally  true  if  the  vertical  axis 
were  shorter  ? — give  short,  square  prisms  to  examine. 
(Yes.) 

Give  pieces  of  yellow  prussiate  of  potash  to  break : 
Do  they  cleave  with  equal  ease  in  three  ways  ?    (No.) 

Are  the  three  faces  about  a  solid  angle  of  equal  luster 
or  shine  ?    (No.) 

Hold  your  skeleton  axes  and  square  prism  side  by 
side,  and  tell  me  if  it  would  be  possible  for  the  two  lateral 
(horizontal)  axes  to  run  from  the  middle  of  one  vertical 
edge  to  the  middle  of  another  and  have  all  agree  with 
this  system  ?    (Yes.) 

13.  Now  let  us  make  the  third  system.  It  is  called  the 
"trimetric."    Why?    (Three-measure.) 

How  many  axes  will  you  need  ?     (Three.) 

What  length  ?     (Long,  medium,  and  short.) 

Keep  one  stick  full  length,  and  cut  the  second  so  as  to 
have  the  pieces  one  third  and  two  thirds.  Make  a  clay 
ball,  etc.,  as  before.  (Give  class  rectangular  and  rhombic 
prisms.)  Compare  your  axes  with  those  solids  and  see  if 
they  agree.  (The  class  will  probably  be  troubled  by  the 
rhombic  prism,  their  only  clew  being  the  last  question 
under  the  second  system.  Have  it  stood  on  the  rhombic 
base,  and  they  will  probably  see  that  the  axis  must  run 
from  edge  to  edge  to  be  at  right  angles  and  of  two  lengths.) 

Now  each  one  tell  me  something  about  our  trimetric 
system.  (Three  axes,  at  right  angles  to  each  other,  of 
three  lengths,  the  bases— top  and  bottom—  rectangles  or 
rhombs ;  the  prisms  erect  on  the  base,  the  lateral  faces 
similar ;  the  solid  angles  may  or  may  not  be  "  square  cor- 
ners," and  the  cleavage  (see  potassium-nitrate  crystals) 
is  different  in  all  three  ways.) 

(Remind  the  class  to  keep  the  specimens  for  the  re- 
quired collection.) 


CRYSTALS  AND  CRYSTALLIZATION.  235 

14.  Review  the  three  systems  given. 

How  can  the  crystals  vary  further  ?  (Can  change  the 
angles  of  the  axis.) 

Our  fourth  system  of  crystals  is  called  the  "  monoclinic" 
(one  incline),  as  one  axis  is  not  at  right  angles  to  hoth  of 
the  others.  Make  three  axes,  as  in  the  trimetric,  and  put 
them  through  the  clay  ball  as  before.  In  the  first  three 
systems  a  knife  passed  straight  down  and  exactly  split- 
ting the  vertical  axis  would  also  split  one  or  the  other  of 
the  lateral  axes.  Now  fix  the  vertical  axes  of  our  mono- 
clinic  form  so  that  while  a  knife  would  split  both  verti- 
cal and  lateral  one  way,  it  could  not  do  so  the  other.  In 
other  words,  have  the  vertical  axis  inclined  a  little  to- 
ward one  lateral,  so  that  the  angles  will  not  be  right  an- 
gles. Compare  this  with  the  oblique  rectangular  or 
rhombic  prisms. 

Now  tell  me  about  them.  (Three  axes,  of  three 
lengths,  two  at  right  angles  and  the  third  inclined  to  one 
of  the  others ;  angles  between  the  edges  of  three  kinds, 
right,  acute,  and  obtuse;  cleavage  differs  (see  mica  or 
gypsum)  in  all  three  directions.) 

15.  The  fifth  system  of  crystals  is  called  "triclinic" 
(three  inclined),  as  a  box  crushed  out  of  square  in  two 
ways  at  once.  The  axes  are  three,  and  all  unequal.  Make 
with  sticks,  as  in  the  other  systems.  The  forms  in  this 
are  so  very  complex  we  will  not  try  to  study  them. 

Can  there  be  any  right  angles  ?    (No.) 

Your  crystals  of  copper  sulphate  must  represent  this. 

16.  The  sixth  system  of  crystals  differs  from  all  the 
others  in  having  four  axes.  The  three  lateral  are  equal, 
at  an  angle  of  60°  with  each  other,  and  all  at  right  angles 
with  the  vertical  axis,  which  is  longer  or  shorter  than 
the  others. 

Make  a  clay  bdlll ;  cut  three  half  sticks  and  place  them 
in  a  circle  through  the  clay  (like  the  spokes  of  a  wheel) ; 
then  place  a  whole  stick  (or  two  halves)  where  the  axle 


236  SYSTEMATIC  SCIENCE  TEACHING. 

of  the  wheel  would  be,  at  right  angles  to  the  others. 
Compare  this  with  the  hexagonal  prism. 

The  cleavage  is  basal— pieces  oif  the  end,  as  a  stick  of 
candy  would  break.  This  system  is  called  the  hexagonal, 
from  its  six  sides. 

You  may  now  tell  me  about  this  system.  (Four  axes, 
three  equal,  and  the  vertical  longer  or  shorter ;  the  verti- 
cal at  right  angles  with  the  other  three,  the  sides  rectan- 
gular, and  the  prism  erect  on  its  base.  Right  angles  may 
occur  over  the  basal  edges.) 

Which  of  the  other  systems  does  it  most  resemble  ? 
(Dimetric.)     . 

There  are  crystals  called  rhombohedral,  which  belong 
to  this  section,  and  can  be  known  by  the  equal  faces 
about  the  vertical  axis  being  in  threes,  and  alternate  with 
each  other. 

(Give  rhombohedron,  and  show  the  class  how  to  hold 
it — two  sharpest  angles  at  the  extremities  of  the  vertical 
axis.)  W6  will  not  try  to  learn  now  ivhy  these  belong 
to  the  hexagonal  system.  Gently  break  these  little  pieces 
of  Iceland  spar  to  see  the  beautiful  cleavage. 

Tell  me  about  this  rhombohedral  section  of  the  hex- 
agonal system.  (Faces  in  threes  about  the  vertical  axis, 
and  alternate  with  each  other.) 

17.  To  further  illustrate  and  fix  these  six  systems  read 
"Crystal  Orders"  in  Ethics  of  the  Dust,  and  pursue  some 
plan  like  the  following : 

Let  each  pupil  double  his  handkerchief  till  four  thick 
(a  piece  of  heavy  woolen  or  cotton  flannel  is  better),  and 
lay  it  on  a  level  surface  before  him.  Give  each  twenty 
buckshot  (or  the  little  wooden  balls  used  in  the  kinder- 
garten to  string),  and  lay  them  on  the  soft  cloth,  where 
they  will  not  easily  roll  about.  Each  ball  will  represent 
one  measure. 

Lay  one  ball  by  itself.  What  system  might  this  rep- 
resent ?    (Monometric.) 


CRYSTALS  AND  CRYSTALLIZATION.  237 

Lay  two  balls  in  line.  What  system  ?  (Dimetric — 
two-measure;  1x1x2.) 

Lay  three  balls  in  line.  What  system  ?  (Still  dimet- 
ric; 1x1x3.) 

Lay  four  balls  in  line.  What  ?  (Still  only  two-mesis- 
ure  ;  1 X  1 X  4.) 

Euskin  calls  these  "needle"  crystals,  and  supposes 
they  are  built  by  molecules  in  line.  Do  we  ever  see 
such  ?    (No ;  would  be  too  fine.) 

Lay  two  rows  of  two  each  together.  What  system  ? 
(Dimetric;  1x2x2.) 

If  another  four  were  placed  on  top  ?  (Monometric ; 
2x2x2.) 

If  three  layers  high  and  two  square  ?  (Dimetric ; 
2x2x3.) 

Who  can  tell  us  how  to  make  the  trimetric  ?  (Two 
rows  of  three  each,  etc.) 

Place  four  balls  in  a  square  again.  How  many  of  the 
others  does  each  touch  ?    (Two.) 

See  if  you  can  make  them  touch  three.  (Push  two 
between  the  other  two.) 

What  figure  have  we  now  ?  (Rhomb,  sides  two  and 
two,  angles  unequal.) 

What  system  ?  (Trimetric ;  1x2x2,  separated  a 
little.) 

As  the  balls  will  not  lie  on  each  other,  we  must  omit 
the  oblique  crystals. 

Lay  seven  in  a  heap  and  press  as  closely  together  as 
possible.     What  figure  now  ?     (Hexagon.) 

What  system  ?     (Hexagonal ;  3x3x3x1.) 

18.  Planes  of  Symmetry.— Would  review  the  subject 
by  a  study  of  these.    Proceed  as  follows : 

Place  one  cube  squarely  on  another.  Turn  the  upper 
through  90°  (quarter  round). 

Do  the  edges  again  agree  ?  Try  other  faces.  (Agree 
always.) 


238  SYSTEMATIC  SCIENCE  TEACHING. 

If  a  cube  was  sawn  squarely  into  two  short  prisms 
would  a  quarter  turn  still  make  the  halves  coincide  ?  The 
plane  through  which  the  saw  i3assed  is  then  a  principal 
plane  of  symmetry. 

What  is  its  relation  to  a  principal  axis  ?  (At  right 
angles.) 

Can  other  principal  planes  of  symmetry  be  imagined 
in  a  cube  ?     (Two  more.) 

Can  you  imagine  a  cube  sawn  in  two  similar  halves 
which  would  not  coincide  by  a  quarter  turn  on  each  other? 
(Diagonally  from  corner  to  corner  or  from  edge  to  edge.) 

In  how  many  ways  could  this  be  done  ?  (On  the  two 
diagonals,  and  through  the  four  edges  of  the  upper  face 
to  the  opposite  edges  of  the  lower  face.) 

How  far  must  you  turn  these  halves  to  have  a  cube 
again  ?     (Halfway  round,  or  180°.) 

Can  you  locate  the  axes — "  secondary  "  they  are  called 
— which  will  he  perpendicular  to  these  secondary  planes  ? 
(Edge  to  edge.) 

How  about  their  length  ?    (All  the  same.) 

How  many  planes  of  symmetry  has  the  monometric 
system  ?     (Three  principal  and  six  secondary.) 

How  many  for  the  dimetric  ?  (One  principal  and 
four  secondary.) 

How  many  for  the  hexagonal  ?  (One  principal  and 
six  secondary.) 

How  many  for  the  trimetric  ?  (No  principal,  three 
secondary  at  right  angles.) 

How  many  for  the  monoclinic  ?  (Only  one  second- 
ary plane.) 

(I  am  fully  aware  of  the  difficulties  in  imagining  these 
planes  and  perpendicular  axes,  but  also  know  the  bene- 
ficial effects  of  this  mental  discipline,  and  that  such  ideas 
will  bear  a  rich  fruitage  in  after  years  when  solid  geome- 
try, etc.,  is  taken  up,  to  say  nothing  of  their  utility  in 
the  study  of  crystals  and  minerals.) 


CRYSTALS  AND  CRYSTALLIZATION.  239 

19.  For  this  lesson  introduce  as  many  models  and  per- 
fect crystals  as  can  be  gathered  to  discuss  with  the  class. 
These  should  include  such  forms  as  the  octahedron  and 
dodecahedron  in  the  monometric ;  octahedron  or  prism 
with  pyramidal  end  in  the  dimetric,  trimetric,  and  mono- 
clinic  ;  and  six-sided  prisms  with  six-sided  pyramids 
(quartz),  three-sided  (tourmaline),  and  rhombs  (calcite, 
etc.). 

Gather  the  class  about  you,  help  them  to  classify  each 
specimen  in  its  system  and  give  a  reason  for  their  deci- 
sion, and  lead  them  to  see  that,  no  matter  how  the  cor- 
ners or  edges  of  a  crystal  are  absent  or  replaced,  it  re- 
mains true  to  its  system  unless  you  change  either  axes  or 
angles. 

It  may  be  suggested  that  it  would  be  well  here  to  pro- 
vide potatoes,  chalk,  or  paratRn  to  cut  crystals  from  and 
test  the  matter.  I  have  tried  it  in  various  ways  and 
found  it  beyond  the  children.  Have  had  better  success 
modeling  in  clay,  and  it  may  be  well  for  the  class  to  re- 
place such  of  the  solid  forms  of  Step  XXVI  as  are  miss- 
ing.   Beyond  this  I  would  not  attempt  to  go. 

Nothing  now  remains  but  to  have  the  class  bring  in 
their  collection  of  crystals  and  models  for  inspection  and 
correction. 

These  should  be  arranged  by  each  in  a  box  and  prop- 
erly labeled,  as  they  will  form  a  valuable  aid  in  future 
work,  and  are  worthy  of  a  place  in  any  collection  of 
minerals. 

Next  Step  XXXVII— Minerals. 


STEP  XXXVIL— MINERALS. 

So  far — through  Pebbles  and  Sharp  Stones — there  has 
been  nothing  said  as  to  kinds  of  stones.  In  crystals  this 
difference  began  to  appear,  and  now  that  color,  form, 
and  crystallization  have  prepared  the  way  for  intelligent 
and  correct  perception,  the  pupil  is  ready  to  consider  the 
varying  kinds  of  stones.  All  stones  are  either  minerals 
or  rocks. 

For  these  lessons  we  choose  first  the  component  parts 
(minerals)  of  which  the  aggregations  called  rocks  are 
formed. 

In  the  simple  sorting  of  metals,  minerals,  and  rocks 
the  only  object  was  for  the  child  to  handle  and  see. 

Beginning  with  pebbles,  and  aiming  at  a  gradually 
increasing  demand  on  the  mental  and  manual  powers  of 
the  pupil,  we  have  taken  up  Sharp  Stones,  Study  of  Met- 
als, Molecules,  and  Crystallization. 

In  these  studies  of  the  minerals  I  consider  the  exercise 
of  the  judgment  of  the  highest  importance.  Try  by  all 
possible  means  to  train  each  member  of  the  class  to  scorn 
aid  from  the  teacher  or  from  each  other. 

Object  of  the  Study  of  Minerals.— This  is  briefly : 

A  review  of  the  past  by  its  application. 

The  exercise  of  the  power  of  decision. 

A  knowledge  of  the  properties  of  minerals  in  general. 

An  acquaintance  with  fifty  important  and  typical 
minerals. 

Preparation  for  the  study  of  rocks. 
240 


MINERALS.  241 

Time  needed. — About  thirty  lessons  of  thirty  minutes 
each,  besides  the  field  excursions. 

Material  and  its  Cost. — In  selecting  this  I  have  recog- 
nized the  unconscious  element  in  mental  development, 
and,  while  bringing  before  the  pupil  as  many  points  re- 
garding minerals  as  I  could,  have  also  sought  that  the 
material  should  be  representative  of  all  important  classes 
of  minerals,  and  arranged  in  scientific  order.  Experience 
has  shown  that  when  the  time  came  (in  chemistry,  blow- 
pipe analysis,  and  mineralogy)  the  pupil  has  usually  rec- 
ognized the  order  and  system  in  the  fifty  minerals  he 
formerly  studied,  and  been  greatly  aided,  although  at  the 
time  not  a  word  was  said  to  him. 

The  following  list  has  been  long  in  use  in  my  classes 
and  proved  very  satisfactory.    In  it  the  aim  has  been  to 

1.  Represent  the  principal  classes. 

2.  Illustrate  the  properties  of  minerals. 

3.  Show  the  important  minerals  which  compose 
rocks. 

4.  Include  crystals  of  the  different  systems. 

5.  Be  cheap.  This  to  consist  not  in  poor  material, 
but  in  the  careful  selection,  as  far  as  possible,  of  the  com- 
mon and  easily  obtained  instead  of  the  rare  and,  in  con- 
sequence, costly.  After  each  mineral  I  have  given  some 
of  the  reasons  why  chosen,  and  italicised  the  character- 
istic points. 

List  of  Minerals  to  Use. 

1.  Native  copper — (color  and  element).    Malleable. 

2.  Sulphur — brimstone.  (Color  and  element;  odor 
when  burned ;  electric  with  friction.)  Used  to  make 
matches. 

3.  Graphite — (element;  streak;  hardness  of  I).  Used 
for  pencils  and  crucibles. 

4.  Cleavable  galena — (color;  cleavage;  crystalline 
form).    Ore  of  lead. 

17 


242  SYSTEMATIC  SCIENCE  TEACHING. 

5.  Massive    pyrite— (coZor ;   hardness  of  7 ;    "fool's 
gold"  ;  sulphide  of  iron).     Little  use. 

6.  Sphalerite — {resinous    luster ;      color).      Ore    of 
zinc. 

7.  Cleavable  halite — {taste;   hardness  of  2).    Chlo- 
ride ;  crystalline  form. 

8.  Cleavable   fluorite  —  {hardness    of  J^ ;    octahedral 
cleavage). 

9.  Magnetite— (ma{7?iefic  oxide  of    iron).     Valuable 
iron  ore. 

10.  Massive  hematite — {red  streak;  oxide  of  iron). 
Valuable  iron  ore. 

11.  Specular  hematite — (luster ;  iron  ore). 

12.  Botryoidal  or  fibrous  limonite— (6roifn  streak; 
iron  ore). 

13.  Corundum — {hardness  of  9  ;  tough).    One  source 
of  aluminium. 

14.  Quartz  crystal — {form;  luster;  hardness  of  7). 
Cut  for  "  Alaska  diamonds  "  and  other  cheap  jewelry. 

15.  Smoky  quartz — {color  ;  lack  of  cleavage). 

16.  Agate — {bands  and  origin).    Cut  for  ornamental 
■work. 

17.  Flint — {translucent  quartz).     Indian  arrow  tips 
and  ancient  knives. 

18.  Chalcedony,  botryoidal— (/or/zi ;  hardness  of  7). 

19.  Jasper — {opaque,  red,  yellow,  etc. ;  quartz).     Uses 
same  as  flint. 

20.  Opal — {luster  and  soft  form  of  quartz). 

21.  Augite  crystal — (form;  important  basic   silicate). 
Short  crystals,  not  associated  with  quartz. 

22.  Massive   hornblende— (important  acidic  silicate). 
Long  crystals,  found  with  quartz. 

23.  Bladed  hornblende— (/orm). 

24.  Asbestus — {fibrous  hornblende). 

25.  Topaz  crystal — {rhombic  prism  ;  hardness  of  8). 

26.  Garnet  crystal— (/orm). 


MINERALS.  243 

27.  Chrysolite — (rock  constituent).  Glassy  and  cleav- 
able. 

28.  Epidote — (color  and  rock  constituent).  Peculiar 
green. 

29.  Magnetited  muscovite — (important ;  cleavage  ;  and 
inclosure  of  magnetite).    Used  in  stoves,  etc. 

30.  Biotite — (black,  basic  mica). 

31.  Orthoclase  cleavage  fragment — (very  important 
feldspar  and  rock  former;  hardness  of  0  and  cleav- 
age). 

32.  Orthoclase  crystal. 

33.  Cleavage  oligoclase — (important  triclinic  feldspar, 
showing  characteristic  striations). 

34.  Cleavage  labradorite — (another  of  the  important 
feldspars;  color;  striations). 

35.  Tourmaline  crystal — (form). 

36.  Ta]c— (hardness  of  1 ;  luster;  feel;  flexible). 

37.  Serpentine — (color  and  importance). 

38.  Kaolinite — (china  clay ;  odor  when  moist). 

39.  Chlorite — (color;  important  rock  former). 

40.  Apatite — (hardness  of  5  ;  color). 

41.  Cleavable  barite — (high  specific  gravity). 

42.  Massive  gypsum — (important  rock,  and  used  for 
plaster,  etc.). 

48.  Gypsum  (selenite)  crystal  —  (form  and  cleav- 
age). 

44.  Clear  calcite  rhombs — (form;  hardness  of  3; 
cleavage  and  double  refraction). 

45.  Oolite — (structure;  effervesces  with  acid). 

46.  Chalk — (earthy  ;  form,  of  calcite). 

47.  Cleavable  dolomite — (angles ;  cleavage  and  to  com- 
pare with  calcite ;  hardness  of  3^  to  Jf). 

48.  Cleavable  siderite — (form  and  ore  of  iron). 

49.  Malachite — (color  and  ore  of  copper).  Valuable 
for  ornamental  work. 

50.  Anthracite — (hard  coal).     Useful  to  burn. 


244  SYSTEMATIC  SCIEJSCE  TEACHING. 

Having  decided  on  the  above  list,  or  such  modifica- 
tions of  it  as  experience  or  peculiar  circumstances  may 
direct,  the  next  thing  to  consider  is 

Where  and  how  to  procure  these  Minerals. 

Some  of  the  "sorting"  specimens  of  Step  VIII  will 
do. 

My  practice  has  been  to  look  about  me  and  gather 
such  material  as  I  could,  then  order  the  rest.  As  to 
this,  see  suggestions  in  Steps  VIII  and  XIV. 

Away  from  a  large  city,  where  such  a  variety  of  mate- 
rial is  used  in  manufacture,  and  especially  if  the  teacher 
is  not  familiar  with  minerals,  I  should  order  the  whole 
list,  as  the  few  one  can  pick  up  will  add  but  a  trifle  to 
the  expense.  Order  some  time  ahead,  and  have  them 
come  as  freight. 

The  cost  for  thirty  sets  of  fifty  each  will  be  about 
thirty  dollars,  as  such  material  is  now  abundant.* 

Boxes  to  Store  them  in  will  be  needed.  The  empty 
cigar  boxes  at  a  dealer's  can  not  be  used  again  by  him, 
and  should  cost  nothing,  or  but  a  trifle.  Get  fifty  of 
these  of  the  medium  (fifty-cigar)  size.  Get  some  neat, 
gummed  labels  and  place  them  on  the  ends,  and  pile 
the  boxes  in  order  (1  to  50)  on  the  shelves  of  some 
closet.  The  teacher  or  her  delegated  pupil  can  then  at 
a  moment's  notice  get  any  needed  specimen.  As  you 
put  in  the  specimens,  wrap  any  small  fragments  tliere 
may  be  in  a  paper  and  lay  in  one  end,  as  they  will  be 
needed. 

Boxes  and  Trays  for  the  Class.— Those  of  Step  III  will 
do,  although  each  box  should  hold  twenty-five  trays,  and 
have  a  cover. 

*  The  author  will  cheerfully  give  information  as  to  the 
cheapest  and  best  sources  of  supply  in  answer  to  any  one  ad- 
dressing him  by  letter  (at  Urbana,  111.). 


MINERALS.  245 

I  have  had  strong  cardboard  boxes  12  inches  square 
and  2  inches  deep  made  to  hold  twenty -five  neat  green 
covered  trays  2^  x  2^  inches  square  and  half  an  inch  deep. 
The  boxes  had  the  corners  strengthened  with  cloth,  and 
were  covered  with  a  bronze  paper,  which  did  not  show 
scratches  and  dirt.  They  cost  five  dollars  per  hundred 
for  the  boxes,  and  five  dollars  per  thousand  for  the  trays. 
A  smaller  quantity  might  cost  a  trifle  more. 

Blowpipes  and  clean  charcoal  will  be  needed  to  en- 
courage energetic  work. 

Streak  plates  of  unglazed  tile,  bits  of  sheet  copper  and 
window  glass,  small  hammers,  etc.,  are  already  provided 
for  in  Step  III,  and  the  other  things  needed  can  be 
brought  by  the  pupil. 

Directions  for  the  Pupil— As  so  much  of  the  value  of 
these  lessons  depends  on  individual  work,  I  had  the  fol- 
lowing little  guide  printed  in  1881  and  loaned  it  to  each 
pupil  to  work  by.  Slightly  modified,  as  experience  has 
shown  wise,  it  is  as  follows : 

How  TO  Study  Minerals. 

All  stones  are  either  minerals  or  rocks. 

A  mineral  is  the  same  all  through,  like  chalk  or  alum ; 
while  a  rock  is  like  fruit  cake  or  nut  candy,  being  made 
of  several  things  put  together. 

For  study  you  will  need : 

1.  A  steel  knife  or  small,  fine  file,  magnetized  by 
rubbing  it  on  a  magnet  until  it  picks  up  fine  iron 
filings. 

2.  A  pocket  magnifier. 

3.  A  piece  of  window  glass. 

4.  A  piece  of  sheet  copper. 

5.  A  "  streak  plate "  of  unglazed  porcelain,  tile,  or 
scythe  stone. 

6.  Small  hammer,  and  piece  of  iron  to  pound  on. 

7.  Notebook  and  pencil. 


24:6  SYSTEMATIC  SCIENCE  TEACHING. 

First  select  the  mineral  you  wish  to  study,  and  then 

follow  this 

Order  of  Work. 

Observe  and  write  in  your  notebook : 

1.  The  Color.    This  may  be  metallic  and 

Copper  red,  Silver  white, 

Bronze  yellow,  Lead  gray, 

Brass  yellow,  Iron  black. 

Gold  yellow,  Steel  gray, 

Or  unmetallic,  and  some  shade  of 

White  (snow,  reddish,  yellowish,  or  greenish). 
Gray  (bluish,  smoke,  pearl,  greenish,  or  ash). 
Black  (velvet,  greenish,  bluish,  grayish). 
Blue  (violet,  sky,  or  indigo). 

Green  (emerald,  olive,  grass,  yellowish,  or  blackish), 
Yellow  (sulphur,  straw,  wax,  ocher,  honey,  orange), 
Eed  (scarlet,  blood,  flesh,  brick,  rose,  cherry). 
Brown  (hair,  chestnut,  reddish,  yellowish,  or  wood). 

2.  The  mark  which  a  pencil  leaves  on  a  slate  is  its 
"streak,"  and  when  sharpened  its  powder  is  called  the 
"  streak  powder." 

A  lead-pencil  mark  on  paper  or  chalk  on  the  black- 
board are  other  illustrations  of  the  same  thing.  Now  get 
the  streak  and  streak  powder  of  your  specimen  and  notice 
its  color^  and  whether  shining  or  dull,  metallic  or  un- 
metallic. 

3.  The  Hardness.  A  few  trials  will  show  you  that 
minerals  diflPer  in  the  ease  with  which  you  can  get  their 
"  streak,"  some  marking  your  plate  easily,  like  chalk  or  a 
pencil,  others  less  easily,  like  copper ;  while  some,  as  flint, 
instead  of  giving  a  streak,  scratch  your  plate,  and,  on  try- 
ing, you  find  you  can  not  cut  or  file  them ;  they  are  too 
"  hard."  Now,  the  reason  of  this  is  that  the  molecules  or 
little  grains  of  those  we  call  "  hard  "  are  fastened  to  each 
other  more  tightly  than  those  of  others  which  we  call 
"  soft:' 


MINERALS.  247 

When  you  rub  a  mineral  on  one  harder  than  itself  it 
leaves  a  streak,  but  when  on  one  softer  it  scratches  it ; 
just  as  the  slate  pencil  left  a  mark  on  the  slate,  but  the 
slate  would  scratch  the  pencil. 

This  hardness  is  a  very  important  point  about  a  min- 
eral, and  the  following  table  is  what  we  compare  others 
with,  and  is  called  the 

Scale  of  Hardness. 

(1)  Talc  ;  can  be  scratched  by  the  thumb  nail. 

(2)  Rock  salt;  cuts  easily,  but  will  not  scratch 
copper. 

(3)  Calcspar ;  cuts  harder  than  "2,"  and  scratches 
copper  a  little. 

(4)  Fluorspar  ;  hard  to  cut ;  scratches  copper  easily. 

(5)  Apatite;  scratches  "3"  easily  and  "4''  a  little; 
will  not  scratch  glass. 

(6)  Feldspar ;  can  hardly  be  cut,  and  scratches  glass 
a  little. 

(7)  Quartz ;  can  not  be  cut  at  all ;  scratches  glass 
easily. 

(8)  Topaz  ;  scratches  "  6  "  easily  and  "  7  "  a  little. 

(9)  Corundum  ;  scratches  "  7  "  easily. 

(10)  Diamond ;  hardest  of  all. 

Test  such  of  these  minerals  as  you  can,  and  then,  re- 
membering how  your  specimen  acted  when  getting  the 
streak,  test  it  with  knife  or  file,  glass  and  copper,  till  you 
decide  which  number  in  the  scale  it  is  most  like,  and 
write  that  for  its  hardness.  Thus,  if  it  gave  a  streak 
easily,  but  only  scratches  copper  a  little,  its  hardness  is 
"  3  "  ;  if  it  scratched  your  streak  plate  and  glass  easily^  it 
is  "7,"  and  may  be  "8"  or  "  9." 

4,  Is  it  magnetic?  Test  this  by  seeing  if  your  mag- 
netized knife  will  pick  up  the  streak  powder. 

5.  Diaphaneity  (letting  Jight  pass  through).  Look  at 
a  thin  edge  or  piece  and  decide  whether  it  is 


248  SYSTEMATIC  SCIENCE  TEACHING. 

1.  Transparent — can  read  through  it;  like  glass  or 
rock  crystal. 

2.  Semitransparent  —  can  see  indistinctly;  smoked 
glass,  rock  salt. 

3.  Translucent^]  ight  comes  through,  but  can  see  noth- 
ing ;  lump  sugar,  porcelain. 

4.  Opaque — no  light ;  as  coal  or  iron. 

6.  Luster,  or  shine  of  the  surface.  This  depends  on 
how  the  light  is  reflected,  and  may  be 

Metallic,  like  metals  or  galena. 

Vitreous,  like  glass. 

Resinous,  as  rosin. 

Pearly,  like  a  pearl. 

Silky,  when  in  threads,  and  bright. 

When  a  mineral  has  no  luster  it  is  said  to  be  dull. 

7.  Tenacity.  Pound  a  piece  gently  with  your  ham- 
mer, or  cut  with  a  knife,  and  decide  which  of  the  follow- 
ing it  is  most  like : 

Brittle,  breaks  in  pieces  easily — galena  or  quartz. 
Tough,  hard  to  break — corundum. 
Malleable,  flattens  without  breaking — copper. 
Sectile,  can  be  cut  into  layers  or  shavings  —  mica, 
lead. 

8.  Cleavage,  or  the  way  it  breaks.  This  you  will  ob- 
serve when  finding  the  tenacity,  and  is 

Perfect  when  some  (at  least)  of  the  pieces  are  regular 
in  shape  and  have  smooth  faces,  like  galena,  calcspar,  or 
rock  salt. 

Hackly,  when  the  surface  is  rough  and  sharp  to  the 
touch. 

Conchoidal,  or  shell-like,  when  breaking  in  rounded 
hollows  and  elevations. 

9.  Stmctlire.  If  the  cleavage  is  more  or  less  perfect 
it  is  because  the  piece  you  broke  was  made  up  of  smaller 
parts  put  together  in  some  particular  way,  and  this  way 
is  the  structure.    It  is 


MINERALS.  249 

Fibrous,  when  threadlike.    These  fibers  are 
Parallel,  when  side  by  side,  or 
Eadiated,  when  running  out  from  one  point. 

Lamellar,  when  in  plates  or  layers,  and 

Micaceous,  when  these  leaves  are  very  thin  and  elastic. 

Coarse  granular,  when  composed  of  large  grains. 

Fine  granular,  when  of  fine  grains. 

Oolitic,  when  made  of  little  egg-shaped  grains  ce- 
mented together. 

Amorphous,  when  the  kind  of  parts  can  not  be  seen. 

10.  Crystals.  If  your  specimen  or  any  of  the  pieces 
are  regular  in  form,  count  the  number  of  sides  around  the 
crystal  and  the  number  and  shape  of  the  faces  forming 
the  end.  If  it  is  a  fragment,  see  whether  the  cleavage  is 
equally  perfect  in  all  directions,  or  only  in  one  or  two 
ways,  and  what  kind  of  angles  you  find. 

You  will  now  be  ready  to  decide  which  of  the  six  sys- 
tems of  crystals  it  belongs  to. 

Some  of  the  simplest  ways  of  knowing  each  system 
are  as  follows : 

Isometinc.  Groups  of  four  or  eight  similar  planes 
about  each  cubic  axis,  and  three  or  six  similar  planes 
about  each  octahedral  axis.  Cleavage  equal  in  all  three 
directions. 

Dimetric.  Groups  of  four  or  eight  similar  planes 
about  the  ends  of  the  vertical  axis  only.  Basal  cleavage 
differs  from  the  other  two. 

Trimetric.  Prisms  are  rhoTnbic.  No  two  cleavages 
alike. 

Monoclinic.  The  group  of  planes  about  any  axis  will 
be  unlike  in  shape.  Right  angles  found  only  over  the 
edges  around  the  crystal.  Cleavage  differs  in  all  three 
ways. 

Triclinic.    No  angle  of  90°. 

Hexagonal.  Groups  of  three,  six,  or  twelve  similar 
planes  about  the  ends  of  the  vertical  axis. 


250  SYSTEMATIC  SCIENCE  TEACHING. 

Tell,  if  you  can,  what  minerals  the  crystal  has  grown 
among. 

If  the  crystal  has  any  substances  inside  of  it,  tell  how 
they  look. 

11.  Microscope.  See  if  it  shows  you  any  lines  or  any- 
thing else  the  eye  could  not  see. 

12.  Feeling.  Has  it  a  soapy  or  greasy  feeling  ?  Is  it 
lights  medium,  or  heavy  ? 

13.  Specific  gpravity.  This  more  exact  way  of  finding 
the  relative  weights  of  minerals,  which  is  so  important, 
is  done  as  follows : 

(1)  Weigh  a  piece  of  the  pure  and  dry  mineral  in  the 
air — say  10.4  grammes. 

(2)  Hang  by  a  fine  wire  and  weigh  in  water — say  6.4 
grammes. 

(3)  Subtract  weight  in  water  from  weight  in  air — 10.4— 
6.4  =  4  grammes. 

(4)  Divide  weight  in  air  by  loss  of  weight  in  water — 

10  4 

—^  =  2.6  specific  gravity. 

This  mineral  (quartz),  then,  is  2.6  times  as  heavy  as 
an  equal  bulk  of  water,  and  2.6  is  called  its  specific 
gravity. 

Find  in  the  same  way  the  specific  gravity  of  five  other 
minerals. 

14.  SmelL    Has  it  any  ?    Breathe  on  it,  and  see. 

15.  Has  it  taste? 

16.  Acid.  Sprinkle  some  of  the  powder  in  a  drop  or 
two  of  acid  on  your  glass  plate  and  see  if  it 

Effervesces  (bubbles  come  off). 
Dissolves,  all  or  in  part ;  and,  if  so. 
Of  what  color  is  the  solution  ? 

17.  If  your  own,  gum  a  number  in  some  hollow  of 
the  specimen.  Then  write  the  number  in  a  little  note- 
book, and  after  it  the  name,  if  known,  and  where  it  came 
from.    Then  place  in  your  cabinet. 


MINERALS.  251 


Blowpipe  Work. 

Much  can  be  found  out  about  a  mineral  by  this  sim- 
ple tool.  One  costing  twenty  cents  will  do.  You  also 
need  an  alcohol  lamp  (or  gas),  a  piece  of  firm  charcoal, 
pincers,  a  little  red  litmus  paper,  and  little  labeled  bottles 
with  pure  soda.  Do  not  try  to  heat  a  piece  of  mineral 
larger  than  a  pin  head.  Always  use  a  side  of  the  coal 
showing  the  rings.  Others  will  snap.  Scrape  a  clean 
place  for  each  new  test.    Proceed  as  follows : 

1.  Heat  a  piece  of  the  mineral  strongly  (on  coal).  If 
it  hums,  note  the  color  of  the  flame  and  the  odor.  If  it 
melts,  does  it  smoke  ?  Is  there  any  colored  coating  left 
on  the  coal  ?  Does  it  glow,  or  change  in  any  way  if  it 
neither  burns  nor  melts  ? 

2.  Is  the  piece  magnetic^  malleable,  or  brittle  after 
heating  ? 

3.  Laid  on  a  bit  of  wet  red  litmus,  does  it  turn  the  pa- 
per blue  ? 

4.  Mix  equal  parts  of  pure  soda  and  powdered  mineral. 
Fuse  strongly,  and  place  on  wet  acetate-of-lead  paper  to 
test  for  sulphur  (black). 

5.  After  the  sulphur  test,  crush  the  mass  on  the  lead 
paper  and  wash  in  a  little  dish.  When  dry,  look  for  iron 
with  the  magnet,  and  for  other  metals  with  the  lens. 

Preparation  of  the  Teacher.— Much  will  already  have 
been  gained  in  the  ordering  and  gathering  of  the  mate- 
rial and  putting  it  away. 

Books  to  consult  will  be  needed.  Those  most  helpful 
to  me  have  been  Dana's  Manual  of  Mineralogy  and  Lithol- 
ogy;  Crosby's  Common  Minerals  and  Rocks,  edition  of 
1887;  and  Winchell's  Geological  Excursions. 

As  in  the  molecule  lessons,  so  here,  I  would  advise  the 
teacher  to  call  one  or  two  friends  or  bright  pupils  to  aid 
in  the  work  of  getting  and  arranging  the  material,  and 
in  making  that  preparatory  trial  of  a  series  of  lessons 


252  SYSTEMATIC  SCIENCE  TEACHING. 

which  so  lightens  the  class  work  and  at  the  same  time 
adds  to  its  efficiency. 

A  notebook  of  not  less  than  sixty  pages,  and  opening 
at  the  end,  will  be  needed.  The  easiest  kind  to  get,  and 
at  the  same  time  the  best,  is  one  ruled  witli  money  col- 
umns, and  having  not  less  than  twenty  lines  to  a  page. 
The  paper  should  be  tough,  and  take  a  pencil-mark  well. 

A  red-rimmed  label  on  the  cover  (be  sure  it  opens  so 
that  the  broad  heading  space  on  each  double  page  is  at 
the  top)  is  easier  seen  than  writing  on  the  brown  manilla 
cardboard.  As  this  book  is  to  be  a  model  for  the  class, 
place  the  notes  and  suggestions  so  helpful  to  the  teacher 
on  the  last  pages,  and  begin  it  as  follows : 

First  page :  Name  of  lessons  and  when  begun  (and 
finished  finally).    Second  and  third  pages  :  head  with 

How  TO  Study  Minerals. 

Read  the  guide,  and  compare  with  the  following  frag- 
ments: 

Copper  (sheet).  Quartz. 

Galena.  Orthoclase. 

Rock  salt.  Magnetite. 

Mica.  Sulphur. 

Talc.  Asbestus. 

Calcite.  Corundum. 

Fluorspar. 
These  fragments  should  be  taken  from  the  "sorting" 
materials  of  Step  VIII,  or  from  the  bits  too  small  to  use  as 
specimens  for  class  work.  Compare  the  little  guide  and 
these  specimens,  which  will  sufficiently  illustrate  the  six- 
teen points.    Keep  no  notes. 

Fourth  page :  Head  it  with  the  first  mineral  and  its 
locality ;  and  along  the  left-hand  side  write  on  successive 
lines  the  sixteen  points  to  be  determined,  adding  the  word 
"  differences  "  after  "  acid." 

Head  the  following  forty-nine  pages  with  the  succeed- 


MINERALS. 


253 


ing  minerals  in  the  list ;  under  each,  to  the  left  of  the 
date  lines,  place  the  sixteen  points  to  be  noted ;  abbrevi- 
ating after  the  first  few  pages  to  Col.,  Str.,  H,,  Mag.,  Dia., 
Lus.,  Ten.,  Clea.,  Struc,  Xs,  Mic,  Feel.,  Sp.  gr.,  etc.,  to 
Diffs.  Then,  in  order,  determine  each  point  about  the 
mineral  in  hand,  and  write  in  pencil  the  decision  on  the 
proper  line.  The  first  (native  copper  from  Lake  Superior) 
will,  when  done,  look  as  follows : 

NATIVE  COPPER— LAKE  SUPERIOR. 


Color, 

Copper  red. 

Streak, 

Same,  and  metallic. 

Hardness, 

2f 

Magnet, 

0. 

Diaphan., 

Opaque. 

Luster, 

Metallic. 

Tenacity, 

Malleable. 

Cleavage, 

0. 

Structure, 

0. 

Crystals, 

0. 

Microscope, 

0. 

Feeling, 

0. 

Sp.  gr., 

8.80. 

Smell, 

0. 

Taste, 

0. 

Acid, 

0. 

Differences. 

The  differences,  which  are  such  a  helpful  feature  of 
Dana's  book,  are  to  be  left  till  the  whole  fifty  minerals 
have  been  studied,  when  the  class  can  unite  in  the  very 
helpful  exercise  of  deciding  in  what  respect  the  mineral 
in  hand  differs  from  all  the  other  fifty. 

TTses  might  be  added  if  time  permits,  but  I  should  let 
the  pupils  look  it  up  alone,  and  then  correct  in  a  general 
exercise. 


254  SYSTEMATIC  SCIENCE  TEACHING. 

Now  let  the  teacher  and  companions  compare  "cop- 
per "  with  the  notes  given,  and  then  each  unaided  work 
out  the  next  four  specimens.  To  test  their  results,  com- 
pare with  Dana,  and  correct  if  need  be.  A  few  difficul- 
ties may  arise  from  the  condensed  directions  of  the 
guide. 

1.  Color.     Of  this  little  need  be  said. 

2.  Streak.  Will  explain  itself.  Make  a  series,  as  ad- 
vised in  metals. 

3.  Hardness.  Teach  the  pupils  always  to  try  the  glass 
first,  copper  next,  and  finger  nail  last,  which  will  save 
trouble. 

Also  caution  against  injuring  the  edges  of  a  crystal  or 
nice  specimen  with  the  knife  or  file.  For  such  tests  choose 
some  broken  or  unimportant  corner  or  surface. 

4.  Magnet.  Use  the  powder  made  in  getting  the  streak, 
both  to  save  material  and  time.  Some  pupils  have  no  idea 
of  economy  of  either,  and  it  is  a  needed  lesson.  One  test 
with  the  knife  over  a  bit  of  white  paper  should  answer 
for  " streak,"  "  hardness,"  "magnet,"  and,  in  the  majority 
of  cases,  all  questions  in  "structure." 

5.  Diaphaneity.    Always  choose  thin  edges  or  pieces. 

6.  Luster.  Scaly  minerals  usually  have  a  pearly 
luster. 

7.  Tenacity.  In  getting  the  hardness  or  streak  nearly 
all  points  under  this  head  will  be  observed.  Still,  it  is 
well  to  take  some  fragment,  and,  having  broken  it  by  gen- 
tle taps  with  a  light  hammer,  examine  the  fragments  with 
the  microscope  for  the  cleavage  and  crystalline  form  dis- 
closed. Caution  the  class  against  breaking  up  crystals 
or  large  specimens,  and,  to  remove  all  temptations,  give  a 
little  fragment  of  each,  if  possible,  for  them  to  use  in  all 
testing  which  involves  injury  to  the  large  specimens. 

8.  Cleavage  will  be  seen  from  the  large  specimens, 
which  will  usually  be  fragments,  and  from  the  breaking 
when  finding  tenacity.    If  it  is  an  unbroken  crystal^ 


MINERALS.  255 

nothing  can  be  told  unless  a  frag-ment  can  be  had.  Dis- 
tinguish between  the  smooth  face  a  crystal  may  have 
taken  in  growing  from  the  similar  surface  due  to  cleav- 
age. Quartz,  for  example,  grows  in  smooth-faced  crys- 
tals, but  has  no  cleavage,  breaking  like  glass.  "Hackly" 
and  "  conchoidal "  are  not  strictly  "  cleavage,"  but  "  frac- 
ture," still  the  distinction  is  not  worth  making  here. 

9.  Structure.  This  is  mainly  the  result  of  crystals 
being  crowded  together  when  growing,  but  may  be  from 
different  causes,  as  in  oolite,  where  the  "  similar  parts  " 
(as  I  have  called  them,  to  include  all)  are  not  crystals. 

Of  course  the  structure  of  a  mineral  which  does  not 
break  (copper)  can  not  be  told.  It  is  amorphous  when 
(like  opal  or  coal)  nothing  can  be  seen. 

10.  Crystals.  Omit  the  "  systems  "  if  too  hard,  as  they 
frequently  will  be,  although  I  believe  more  can  be  done 
than  is  usually  supposed  if  form  has  been  well  taught. 
Have  them  drawn  if  the  class  be  able. 

11.  Microscope.  Each  child  should  be  encouraged  to 
get  a  small  pocket  lens.  If  purchased  by  one  of  the 
class  at  dozen  rates  they  are  very  cheap  (twenty-five  to 
thirty  cents  for  three-quarter-inch  lens  in  rubber  holder). 

12.  Feeling.  Let  each  child  exercise  its  judgment  as 
regards  comparative  weight,  calling  those  about  like 
quartz,  "  light "  ;  those  like  hematite,  "  medium  "  ;  and 
those  like  galena,  "  heavy." 

13.  Specific  gravity.  Scales  and  fine  weights  will  be 
needed  for  this  work,  which  I  introduce  here  not  only 
for  the  mineral  work,  but  to  give  the  child  a  practical 
acquaintance  with  the  metric  system  of  weights.  Metric 
lengths  and  volume  have  been  already  given  (Steps  XXI, 
XXVI,  and  XXXI),  and  weight  has  been  delayed  only 
till  a  suitable  time  came,  when  it  would  be  of  real  use. 

Scales  and  weights  are  not  as  expensive  as  might  be 
thought.  A  "prescription  balance,"  having  an  extra 
weighted  hook  to  replace  one  of  the  pans,  and  costing 


256  SYSTEMATIC  SCIENCE  TEACHING. 

under  five  dollars,  will  do  as  well  for  the  pupils  as  a 
twenty-dollar  balance  (made  expressly  for  such  work), 
and  can  be  used  for  other  things. 

The  weights  will  be  extra.  Brass  ones  from  twenty 
grammes  to  half  a  centigramme  can  be  had  for  eighty 
cents ;  or  buy  the  brass  weights  from  twenty  grammes  to 
one  decigramme,  and  twenty-five  cents'  worth  of  alu- 
minum wire.  When  buying,  have  the  wire  accurately 
weighed  in  milligrammes.  Measure  the  whole  piece  in 
millimetres,  and  estimate  how  many  millimetres  in  length 
for  five-,  two-,  one-,  and  a  half -centigramme  weights,  and 
with  strong  scissors  cut  off  as  exactly  as  possible  bits  of 
the  lengths  required,  cutting  two  of  the  two-centigramme 
weights  to  each  set  of  the  others. 

Bend  the  five-centigramme  piece  with  three  angles, 
one  angle  to  each  of  the  two  two-centigramme  bits  needed, 
and  leave  the  one  -  centigramme  and  half  -  centigramme 
bits  straight.  The  quarter's  worth  of  wire  will  make  quite 
a  number  of  sets  of  these  weights,  and  I  would  advise 
cutting  it  all  up  while  at  it,  as  such  weights  are  apt  to 
be  lost.  Use  the  pincers  of  Step  XXV  to  pick  up  the 
weights,  which  must  never  be  put  down  except  in  scale 
pan  or  hox.  Five  such  scales  and  sets  of  weights  w411  do 
quite  well  for  a  class  of  thirty.  Use  fine  copper  wire  to 
hang  the  specimen  by,  as  it  is  much  easier  to  fasten 
around  and  adjust  than  thread.  I  would  weigh  several 
specimens  with  the  class,  and  let  them  figure  out  the  re- 
sults with  you  before  the  pupils  try,  and  when  they  begin 
let  them  verify  one  or  two  of  those  results  first.  If  these 
precautions  are  observed  the  class  will  do  excellent  work 
from  the  start. 

14.  Smell.  Tests  on  hot  iron  should  be  made  out  of 
school,  unless  the  class  has  a  room  to  itself  or  meets  after 
the  rest  of  the  pupils  have  gone  home. 

15.  Taste.  Few  minerals  have  taste,  but  if  the  halite 
(rock  salt)  is  valued  much  it  should  be  taken  away  after 


MINERALS.  257 

testing",  as  many  children  seem  to  crave  salt,  and  "  taste  " 
till  but  little  is  left. 

16.  Acid.  I  have  had  no  end  of  trouble  from  pupils 
reversing  the  directions.  Never  put  acid  on  a  mineral, 
but  always  put  small  bits  of  mineral  in  the  acid,  when 
they  can  be  watched  and  results  noted.  Look  out  for  the 
clothes,  or  acid  may  ruin  them. 

With  specimens,  boxes  and  trays,  little  books  of  direc- 
tions, acid-,  etc.,  ready,  and  the  personal  acquaintance  with 
the  material  derived  from  the  foregoing  study  of  the  fifty 
specimens  to  be  given  the  pupil,  the  teacher  is  now  pre- 
pared for  class  work. 

The  Lessons. 

There  will  be  two  stages  in  these  :  1,  to  compare  terms 
with  wisely  chosen  material;  2,  to  compare  minerals 
with  descriptions. 

Lesson  1.— Give  each  pupil  a  box,  25  trays,  a  streak 
plate,  bit  of  sheet  copper,  bit  of  unscratched  window  glass, 
a  notebook,  and  a  copy  of  How  to  Study  Minerals.  Let 
the  class  prepare  blank  labels  about  1^  x  2  inches  {narrow 
strips  get  displaced,  and  those  too  large  for  the  trays  look 
untidy),  and  neatly  copy  after  the  teacher  while  he  writes 
on  the  board  the  names  and  localities  of  the  thirteen 
fragments  to  use  in  explaining  the  guide  and  first  two 
pages  of  notebook.  Place  these  labels  in  the  trays,  begin- 
ning at  the  upper  left-hand  corner,  and  when  the  first 
row  of  five  boxes  is  done  return  to  the  left-hand  tray  of 
the  second  row,  as  in  reading  a  second  line. 

Now  let  the  class  compare  their  labels  while  you  read 
the  list  aloud,  then  give  out  the  thirteen  fragments,  being 
sure  each  pupil  has  one,  as  they  are  to  be  held  account- 
able for  everything  given.  Replace  the  covers  on  the 
boxes,  and  let  each  gum  a  neat  label  on  the  upper  left- 
hand  corner  of  the  box  cover  and  write  his  or  her  name 
plainly  in  ink. 
lb 


258  SYSTEMATIC  SCIENCE  TEACHING. 

Telling  the  class  to  carefully  read  the  guidebook  be- 
fore the  next  lesson,  gather  up  the  boxes  by  rows,  or  in 
some  way  they  can  be  easily  returned,  and  put  where  no 
one  can  disturb  them.  Appoint  some  reliable  pupil  (or 
have  the  class  choose  a  "  committee  ")  to  see  about  lenses, 
also  notebooks  like  yours.  Ask  each  to  bring  a  broken- 
bladed  knife  or  bit  of  old  file. 

Lesson  2. — Distribute  the  boxes.  Remove  the  covers 
and  put  under  the  boxes,  where  they  will  be  out  of  the 
way  and  not  get  torn.  Let  one  pupil  after  another  read 
a  paragraph  of  the  guide,  and  after  each  reading  explain 
or  illustrate  from  the  specimens  in  the  box,  in  every  case 
letting  the  pupils  try  to  discover  the  specimens  in  point, 
and  telling  only  as  a  last  resort.  For  example,  John 
reads,  "  The  color  may  be  metallic  or  unmetallic." 

Tell  me,  John,  which  are  metallic  ?  ("  Copper,  galena, 
magnetite,  and  corundum.") 

Jane,  which  of  the  metallic  colors  have  we  ?  ("  Cop- 
per red,  lead  gray,  and  iron  black.") 

Alice  may  read,  "  Or  unmetallic,  and  some  shade  of 
white." 

You  may  tell  me  which  white  minerals  we  have. 
("  Rock  salt,  calcite,  and  perhaps  others.") 

Are  they  pure  white,  Samuel  ? 

Now  will  come  the  puzzle :  Shall  transparent  mica 
be  called  "  white,"  or  whatever  tinge  it  has  ?  I  have  al- 
ways said  "  Yes,"  just  as  we  speak  of  "  white  "  glass  to 
distinguish  it  from  "  colored." 

Mary,  have  we  any  "  grays  "  ?    So  proceed. 

When  the  class  comes  to  streak,  let  them  mark  (or  try 
to  mark)  a  row  of  the  thirteen  streaks  on  the  tile,  and 
then  discuss  them. 

Hardness.  After  the  caution  given  before  (see  Prepa- 
ration of  Teacher)  let  the  class  try  cutting  the  specimens 
given  in  the  scale  from  1  to  9,  and  observe  the  color 
of  streak  powder,  magnetism,  and  tenacity  as  it  is  done, 


MINERALS.  259 

Explain  to  thera  that  if  the  copper  is  scratched  by  a 
mineral  hard  enough  to  scratch  glass,  time  is  lost  and  the 
copper  spoiled  to  no  purpose,  and  so  the  regular  order 
should  be,  first,  the  nail ;  if  that  fails,  try  glass ;  not 
scratching  glass,  try  the  copper.  Following  this  plan,  let 
the  class  all  together  go  over  the  thirteen  specimens  and 
determine  the  hardness.  In  practice,  the  knife  should  be 
the  main  reliance,  and  each  pupil  should  learn  to  use  it 
in  such  a  way  as  to  give  exact  results.  Do  not  whittle 
(as  a  stick),  but,  holding  the  specimen  firmly  between  the 
thumb  and  finger  of  the  left  hand,  place  it  against  the 
thumb  of  the  right  and  cut  toward  you,  as  in  pointing  a 
pencil. 

Spelling  lessons  during  these  days  should  be  drawn 
from  the  guide. 

Lesson  3. — Diaphaneity  need  not  take  long. 

Luster  is  also  easy. 

Tenacity.  The  cutting  will  answer  nearly  all  these 
points  ;  others  can  be  found  with  the  hammer. 

Cleavage  will  be  quickly  understood. 

Structure  has  already  been  explained. 

Five  at  least  of  the  thirteen  test  specimens  will  show 
the  crystalline  form,  and  the  teacher  must  decide  what  is 
to  be  done,  and  see  that  it  is  understood. 

The  lens  should  have  been  used  all  along. 

Feeling  will  probably  complete  this  lesson. 

Lesson  4. — Specific  gravity  has  already  been  spoken 
of.  A  word  as  to  the  method  of  weighing  and  handling 
of  the  weights.  We  will  verify  the  specific  gravity  of  the 
quartz  given  in  the  guide. 

1.  Dust  off  the  scale  and  see  that  it  balances. 

2.  Place  (never  drop)  a  20-gramme  weight  in  left-hand 
pan,  and  hang  a  piece  of  quartz  by  a  fine  wire  from  the 
right,  at  such  a  height  as  to  be  an  inch  above  the  bottom 
of  a  dry  tumbler  placed  below.  (Should  it  raise  the  20- 
gramme  weight,  choose  a  lighter  piece  of  mineral.) 


260  SYSTEMATIC  SCIENCE  TEACHING. 

3.  Steady  the  left  scale  pan  with  a  finger  while  the  20- 
gramme  weight  is  put  back  in  the  box  and  10  grammes 
put  in.     (Not  enough.) 

4.  Gently  add  5-gramme  weight.     (Too  light.) 

5.  Add  2-gramme  weight.     (Too  heavy.) 

6.  Remove  2-gramme  and  put  in  1-gramme  weight. 
(Too  heavy.) 

7.  Remove  1-gramme  and  put  in  5-decigramme  weight. 
(Too  heavy.) 

8.  Remove  5-decigramme  and  put  in  2-decigramme 
weight.     (Too  light.) 

9.  Add  2-decigramme  weight.     (Too  heavy.) 

10.  Remove  2-decigramme  and  add  1- decigramme 
weight.     (Too  light.) 

11.  Add  5-centigramme  weight.     (Too  heavy.) 

12.  Remove  5-centigramme  and  put  in  2-centi gramme 
weight.     (Too  light.) 

13.  Add  2-centigramme  weight.     (Just  right.) 

14.  Count  up  weights,  writing  each  in  a  column  to 
add. 

10  grammes  +  5  grammes  +  .3  -f  .04  =  15.34  grammes. 
(Weight  in  air.) 

15.  Record  in  notebook. 

Notice  in  the  above  weighing  that  the  adding  and  re- 
ducing of  weights  has  always  been  by  one  half,  as  nearly 
as  the  weights  would  permit.  If  too  heavy  (20  grammes), 
it  was  made  one  half  less  (10  grammes).  Being  too  light 
(10  grammes),  one  half  (5  grammes)  was  added. 

16.  Fill  the  tumbler  with  cold  water  till  the  specimen 
hangs  entirely  below  the  surface  and  still  clear  of  the 
bottom.  The  15.34  grammes  will  now  be  too  much,  as 
the  immersion  of  the  quartz  has  raised  its  own  bulk  of 
water,  and  is  thereby  buoyed  up  by  the  exact  weight  of 
the  water  raised. 

17.  Return  all  but  the  10-g,  weight  to  the  box.  (Too 
heavy.) 


MINERALS.  261 

18.  Eemove  10-g.  and  put  in  5-g.  weight.    (Too  light.) 

19.  Add  2  g.     (Too  light.) 

20.  Add  2  g.  more.     (Too  light.) 

21.  Add  5  dg.  (1  g.  would  make  10  dg.,  which  we  know 
is  too  much).     (Too  heavy.) 

22.  Eemove  5  dg.  and  put  in  2  dg.     (Too  light.) 

23.  Add  2  dg.     (Too  light.) 

24.  Add  5  eg.     (Too  heavy.) 

25.  Remove  5-cg.  and  put  in  2-cg.  weight.    (Too  light.) 
2Q.  Add  2  eg.     (Just  right.) 

27.  Count  up  weights :  5  +  2  +  2  +  .2  +  .2  +  .02  +  .02 
g.  =  9.44  g.,  the  weight  of  mineral  which  the  water  did 
not  buoy  up. 

28.  How  much  did  it  buoy  up  ?  (Evidently  the  dif- 
ference between  the  dry  weight  and  the  weight  in  water — 
15.34  -  9.44  =  5.90  g. 

Now  this  5.9  g.  is  the  weight  of  a  bulk  of  water  exactly 
equal  to  our  piece  of  quartz,  and  to  find  how  the  weight 
of  quartz  compares  with  water  (which  is  the  standard  for 
liquids  and  solids)  we  divide  the  weight  in  air  by  its  loss 
of  weight  in  watei — 15.34  -?-  5.9  =  2.6,  the  specific  gravity 
of  quartz. 

Smell,  taste,  and  acid  require  no  further  notice,  except 
that  if  small  fragments  of  mineral  are  dropped  into  the 
acid  much  better  and  neater  results  will  be  had  than  from 
the  slovenly  practice  pupils  seem  to  prefer  of  putting 
acid  on  the  specimen. 

Lesson  5. — Before  the  class  meets  let  some  pupil  put 
the  names  and  localities  of  the  first  twenty -five  minerals 
on  the  board  for  the  class  to  write  such  as  are  not  already 
written.  When  the  class  is  ready  for  work,  have  them 
return  the  test  fragment  of  mica  (as  not  needed  in  this 
set),  and  arrange  the  labels  in  order,  putting  those  needed 
in  the  next  box  under  the  twenty-fifth  tray,  and  the  cal- 
cite,  etc.,  belonging  in  the  second  set  (but  needed  here  for 
testing  hardness)  in  the  first  tray. 


262  SYSTEMATIC  SCIENCE  TEACHING. 

Absentees  cause  much  trouble,  and  always,  in  giving 
out  specimens,  provide  for  them  by  the  teacher  or  some 
friend  of  the  absentee  taking  their  boxes  and  doing  for 
them  whatever  the  class  does.  Of  course  this  is  a  loss  to 
the  pupil,  but  beyond  a  cordial  invitation  for  such  to 
come  for  private  direction,  I  should  advise  that  the  work 
move  steadily  on.  One  important  result  of  systematic 
and  progressive  science  work  will  be  found  in  its  redu- 
cing absenteeism  to  the  strictly  unavoidable  limit.  The 
child  will  be  so  interested  that,  however  distasteful  other 
work  may  be,  he  will  endure  it  for  the  pleasures  of  the 
science  lesson.  At  least  with  me  it  has  proved  a  leaven 
to  lighten  the  whole  school  work. 

Put  the  model  for  the  fourth  page  of  notebook  on  the 
board  to  be  copied  while  the  distribution  goes  on. 

Distribute  the  twenty  five  specimens.  Be  sure  each 
child  present  and  each  absentee  has  a  full  set  in  addition 
to  the  extra  specimens  of  the  scale  of  hardness,  the  cop- 
per, glass,  tile,  and  guide.  Read  the  heading  and  sixteen 
points  of  fourth  page  to  see  that  all  agree.  Study  first 
specimen  with  the  class. 

Class  write  heading  and  points  of  second  and  third 
minerals,  and  compare  by  public  reading. 

Class  independently  study  and  write  neat  notes  on 
second  and  third. 

Change  notebook  and  publicly  criticise  and  cor- 
rect. 

Collect  notebooks  for  examination  by  teacher  as  to 
accuracy  and  neatness. 

Six  to  thirteen  lessons  will  be  now  spent  in  work  by 
the  pupils,  and  the  teacher  has  nothing  to  do  but  to  say 
"No"  to  those  who  want  too  much  help.  Encourage 
those  "in  the  Valley  of  Indecision,"  and  amid  the  bustle 
of  work  keep  the  pupils  from  interfering  with  or  aiding 
each  other.  The  thorough  prepai*ation  will  now  bear 
fruit. 


MINERALS.  263 

Prompt,  accurate  work.  Encourage  by  the  promise  of 
a  reward  for  those  who  finish  in  time,  which  reward  may- 
be anything  the  teacher  chooses,  but  with  me  has  taken 
the  helpful  shape  of  blowpipe  work,  of  which  more  will 
be  said  in  the  proper  place. 

Punishment  for  the  lazy  and  indifferent,  always  to  be 
found,  will  be  the  direct  result  of  such  conduct — they 
simply  punish  themselves  by  losing  the  benefits  from  the 
lessons,  and  nothing  more  is  needed. 

The  class  will  be  somewhat  hampered  by  the  spelling 
and  new  terms.  This  can  be  helped  by  spelling,  as  sug- 
gested in  Lesson  3.  The  pupils  will  only  do  two  or  three 
minerals  the  first  day  of  this  work,  and  perhaps  rise  to 
five  at  the  last.  Never  hurry  them ;  simply  see  that 
steady,  deliberate  use  of  the  time  is  made,  as  another  of 
the  many  valuable  lessons  included  in  this  fertile 
subject. 

Teacher  examine  and  mark  errors  (in  blue  pencil)  as 
fast  as  the  pupils  finish  the  twenty-five  specimens. 

Pupils  correct  errors.  After  marking,  let  the  pupil 
find  his  mistakes  and  correct  them.  Some  misunder- 
standing will  here  be  discovered,  and  can  be  explained. 

Pupils  mix  and  replace.  Errors  corrected,  let  each 
take  his  specimens  and  put  them  in  a  mixed  pile  on  the 
box  cover,  and  then  return  to  the  proper  labels.  This 
sorting  is  a  great  aid.  If  he  fails  in  even  one  mineral  let 
him  repeat. 

Pupils  mix  and  exchange.  When  two  pupils  (not 
seated  too  near  each  other)  have  shown  their  ability  to 
recognize  their  own  specimens  let  each  place  minerals 
in  a  mixed  pile  and  exchange  boxes,  to  sort  those  they 
have  not  seen.  Encourage  the  reference  to  notes  and 
use  of  any  known  tests  in  doing  this.  Suppose  the 
pupil  hesitates  between  hematite  or  limonite.  He  looks, 
and  finds  the  first  has  a  red  streak,  and  the  second  a 
brown.    Taking  his  streak  plate,  the  question  is  at  once 


264  SYSTEMATIC  SCIENCE  TEACHING. 

settled.  When  the  minerals  are  back  in  their  places,  let 
the  two  (in  quiet  tones)  look  the  results  over  together, 
understanding  that  any  objection  is  to  be  backed  up  by  a 
reason  and  proof.  Here  (not  sooner)  is  a  good  place  to 
introduce  the  use  of  Dana's  Manual  as  a  reference  book. 
Encourage  (by  the  discount  the  teacher  can  get)  the  pu- 
pils able  to  oivn  the  book,  which  stands  unequaled  as  a 
clear  and  concise  work.  One  of  the  most  helpful  things 
a  teacher  can  do  (as  soon  as  the  pupil  can  read,  or  sooner 
by  example)  is  to  train  in  the  skillful  use  of  books.  It  is 
not  best,  in  my  judgment,  to  attempt  to  remember  much 
about  things  one  would  not  trust  his  memory  for,  except 
to  know  where  the  data  is  to  be  found,  and  this  covers 
very  much  in  geography  (latitude,  longitude,  etc.),  his- 
tory (dates),  chemistry  (atomic  weights  and  formulae), 
physics  (specific  gravities,  data  regarding  expansion,  etc.), 
mineralogy,  and  other  subjects.  If  such  things  are 
needed,  the  frequent  looking  up  and  use  will  soon  fix 
them  ;  if  not  needed,  who  wants  to  remember  them  ? 

These  bright  and  industrious  pupils  will  now  have 
completed  the  first  stage  of  the  work,  and  know  more  or 
less  perfectly  how  to  look  at  a  mineral,  the  points  of  dif- 
ference, etc. 

The  second  stage  should  continue  and  fix  the  points 
of  the  first,  and  also  teach  the  comparing  of  specimens 
with  written  (or  printed)  descriptions.  It  is  difficult  to 
do  this  satisfactorily  with  a  large  class  working  together, 
so  advantage  can  be  taken  of  the  fact  that  some  finish 
sooner  than  others  to  secure  the  individual  work  needed, 
in  the  following  way  : 

New  boxes  can  be  given,  or  the  first  emptied  and  new 
labels  put  on. 

How  to  empty. — There  are  some  suggestions  which 
will  be  of  aid. 

1.  Pupil  removes  streak  plate,  copper  (sheet),  bit  of 
glass,  notebook,  guide,  labels,  and  any  other  property  be- 


MINERALS.  265 

longing  to  him  or  needed,  and  the  few  fragments  from 
the  test  specimens  which  belong  in  the  second  box. 

2.  He  presents  the  neatly  arranged  set  of  twenty-five 
specimens  to  the  teacher  for  inspection.  If  all  right,  the 
teacher  puts  on  the  cover,  and  by  a  quick  movement 
turns  the  box  upside  down.  The  contents  are  now  in 
the  cover. 

3.  Lift  off  the  box,  and  gathering  up  the  emptied 
trays,  give  them  back  to  the  pupil  to  arrange,  while  the 
specimens  are  gathered  in  the  two  hands  and  laid  (not 
thrown  or  dropped)  in  a  large,  shallow^  box  provided,  and 
the  pupil  is  given  his  cover  again.  All  this  takes  less 
than  thirty  seconds  to  do,  and  the  injury  to  the  specimens 
is  very  slight.  The  subsequent  soi-ting  and  putting  away 
will  be  helpful  to  and  enjoyed  by  the  pupils. 

New  list  on  board. — This  should  be  placed  where  it 
can  remain  for  some  time,  and  as  follows : 

No.  26.  Garnet — reddish,  24-sided  crystals. 

No.  27.  Chrysolite  —  greenish,  glassy  mineral,  with 
cleavage. 

No.  28.  Epidote — yellowish  green  and  opaque. 

No.  29.  Muscovite — splits  in  thin,  elastic  scales. 

No.  30.  Biotite — cleaves  in  thin,  elastic  black  scales. 

No.  31.  Orthoclase  —  hardness  of  6 ;  perfect,  pearly 
cleavage. 

No.  32.  Orthoclase  crystals — angles  around  the  crys- 
tals 9o^ 

No.  33.  Oligoclase — hardness  of  6  ;  yellowish  white ; 
lines  on  cleavage  surface. 

No.  34.  Labradorite — hardness  of  6  ;  grayish ;  stria- 
tions  on  cleavage  surface. 

No.  35.  Tourmaline  crystals — black  ;  6-sided  crystals. 

No.  36.  Talc — hardness  of  1 ;  feels  soapy. 

No.  37.  Serpentine  —  hardness  of  4  ;  greenish ;  clay 
smell. 

No.  38.  Kaolinite — white  and  soft ;  clay  smell. 


266  SYSTEMATIC  SCIENCE  TEACHING. 

No.  39.  Chlorite— dark  green  ;  soft. 

No.  40.  Apatite — hardness  of  5 ;  glassy  green  ;  6-sided 
crystal. 

No.  41.  Barite — white  and  heavy  ;  hardness  of  2  to  3. 

No.  42.  G  ypsum — hardness  of  2 ;  no  effervescence  in 
acid. 

No.  43.  Gypsum  crystal — hardness  of  2 ;  cleavage  in 
flexible  scales. 

No.  44.  Calcite— Iceland  spar ;  laid  over  fine  lines  and 
turned  makes  them  look  double. 

No.  45.  Oolite  (calcite) — structure  oolitic. 

No.  46.  Chalk  (calcite) — white  and  earthy ;  effervesces 
in  cold  acid. 

No.  47.  Dolomite — hardness  of  3^  ;  effervesces  less  free- 
ly than  calcite ;  rhombohedral  crystals. 

No.  48.  Siderite — hardness  of  3^  ;  brownish  and  heavy ; 
rhombohedral  crystals. 

No.  49.  Malachite — beautiful  green;  effervesces  in  acid. 

No.  50.  Anthracite — black  ;  conchoidal  fracture ;  burns 
without  flame. 

I  have  omitted  the  localities,  which  the  teacher  should 
put  in,  and  the  points  given  must  be  made  to  agree  with 
the  material,  which  will  ditt'er  in  some  cases. 

Pupils  as  fast  as  ready  should  head  the  next  twenty- 
five  pages  of  their  notebooks,  and  write  the  sixteen  points 
for  determination  as  before.     Also  prepare  labels. 

The  minerals  are  not  to  be  given  to  the  pupil,  but 
selected  by  him.  Place  one  or  more  shallow  boxes  or 
trays  in  light,  convenient  places  about  the  room,  with 
about  five  specimens  of  each  of  the  second  twenty-five 
minerals  in  every  box.  These  125  specimens  should  be 
mixed  together,  and  when  the  pupil  has  his  box  and 
labels  all  ready  let  him  {alone)  at  one  of  these  mixed  col- 
lections select  his  set  of  twenty-five,  using  the  brief  de- 
scriptions on  the  board  as  an  aid.  He  should  also  be  per- 
mitted to  consult  Dana  if  he  wishes. 


MINERALS.  267 

Boxes  corrected.— When  a  set  has  been  selected,  bring 
to  the  teacher,  who  should  run  over  the  box  and  remove 
any  duplicates.  Let  the  pupil  then  return  these  dupli- 
cates to  the  mixture  and  try  and  fill  the  vacancies.  With 
the  little  direction  and  limited  experience  at  his  com- 
mand, I  would  advise  calling  his  attention  (if  a  second 
failure  results)  to  points  that  will  help  him,  as  it  is  really 
quite  a  difiicult  task  for  him. 

When  he  has  selected  his  twenty-five  different  miner- 
als help  him  to  get  the  specimens  to  correspond  with  the 
labels,  and  then  he  can  start  to  work  and  make  his  deter- 
minations as  before  ;  have  his  notes  marked  ;  correct  his 
mistakes ;  and  sort  his  own  and  some  one  else's  minerals 
till  the  work  can  be  accurately  done.  Now,  as  his  re- 
ward for  prompt,  energetic  study,  will  come 

Blowpipe  Work. — Give  each  pupil,  as  he  satisfactorily 
completes  the  above,  a  lamp,  piece  of  charcoal,  some  bits 
of  galena  the  size  of  a  pin  head,  a  blowpipe,  and  the 
other  things  given  on  the  last  page  of  his  guide,  and  let 
him  take  them  into  some  corner  or  anteroom  where  the 
attention  of  the  others  will  not  be  called  off,  to  do  what 
he  can  with  the  blowpipe. 

Show  (by  a  copy  on  the  board)  how  to  arrange  the 
notes,  which  should  always  be  kept,  and  which  do  so 
much  to  check  trifling  and  aimless  work.  The  following 
is  a  model  of  his  pages  after  testing  galena  and  hematite. 
By  all  means  put  such  notes  on  the  same  page  with  his 
other  determinations  on  the  same  mineral ;  or  by  a  note 
refer  to  the  place  where  these  blowpipe  tests  are  placed. 

Galena— Blowpipe  .  Tests. 

1.  Melted  to  beautiful  globule  ;  yellow  coat  on  coal. 

2.  Brittle,  and  looked  like  galena. 

3.  No  change  to  red  paper. 

4.  Paper  black  =  sulphur. 

5.  Little  flat  scale  of  malleable  lead. 


268  SYSTEMATIC  SCIENCE  TEACHING. 

Hematite — Blowpipe  Tests. 

1.  Eed  hot,  but  no  melting. 

2.  Magnetic  (if  heated  enough). 

3.  No  change  to  red  paper. 

4.  No  sulphur. 

5.  Magnetic  grains  of  iron. 

Provide  trays  of  named  fragments  for  them  to  select 
from,  pyrite,  galena,  hematite,  calcite,  malachite,  oolite, 
gypsum,  sulphur,  siderite,  anthracite,  and  sphalerite  being 
best. 

A  little  oversight  may  be  needed,  but  it  is  a  reward, 
and  the  only  condition  should  be  neat  and  exact  work 
and  notes.  If  they  play  too  much  or  do  not  fulfill  the 
above  conditions,  let  them  forfeit  the  privilege. 

Close  up  this  part  of  the  work  as  soon  as  all  have  had 
a  reasonable  time  to  do  the  work,  those  finishing  last 
having  no  time  for  blowpipe  work. 

Review.— Make  this  a  general  exercise,  as  advised  in 
previous  work,  by  (1)  each  telling  something  they  have 
noticed  ;  (2)  by  a  rapid  questioning  on  terms,  methods,  and 
peculiarities  of  minerals  ;  (3)  by  describing  minerals  from 
memory,  the  class  to  tell  what  is  described. 

After  this  refreshing  of  the  memory  proceed  to  the 
differences,  which  his  study  of  the  whole  fifty  will  now 
make  in  order  and  very  helpful.  My  personal  study  and 
delight  has  always  been  to  seek  the  one  thing  by  which 
a  particular  mineral,  plant,  or  animal  is  characterized, 
by  which  it  can  be  at  once  known.  Failing  to  find 
one,  I  have  sought  the  smallest  possible  combination. 
Increased  knowledge  has  often  obliged  me  to  change  or 
modify  such  "  earmarks,"  but  on  the  whole  it  has  proved 
a  very  helpful  practice.  Make  this  a  general  class  exer- 
cise, letting  them  take  turns  in  telling  how  they  would 
distinguish  some  particular  mineral  from  all  the  rest,  the 
teacher  adding  such  points  as  they  may  not  have  had  a 
chance  to  learn. 


MINERALS.  269 

Many  of  these  points  are  italicized  in  the  list  given 
under  Material ;  also  some  of  the  uses. 

Return  specimens  in  second  box  to  the  teacher,  as  in- 
dicated before. 

Review  of  the  whole.— Let  the  teacher  gather,  from 
private  collections,  school  set,  or  from  friends,  100  or  150 
specimens  of  the  minerals  studied  which  the  class  have 
never  examined.  This  will  average  two  or  three  of  each 
kind,  but  it  will  be  better  to  have  one  or  two  of  the 
less  important  and  four  or  five  of  those  of  frequent  oc- 
currence in  rocks  or  valuable  ores. 

Take  four  to  six  box  covers  and  fill  each  with  twenty- 
five  trays.  In  the  bottom  of  each  tray  (labels  get  mixed) 
mark  in  soft  pencil  numbers  from  1  to  100  or  150.  Now, 
without  any  attempt  at  order,  place  the  new  specimens  in 
the  trays.  When  the  time  comes  place  them  in  light 
places  about  the  room,  or  pass  from  pupil  to  pupil,  who 
should  have  pages  in  their  notebooks  prepared  by  num- 
bers on  the  left-hand  side  of  the  pages  corresponding  to 
those  in  the  boxes,  and  after  each  number  they  are  to 
write  what  they  determine  the  mineral  in  that  tray  to  be. 

Free  use  of  notes,  Dana,  and  any  other  helps  they 
know  of,  should  be  encouraged,  but  tliey  must  not  help 
one  another. 

When  this  test  is  completed  let  the  pupils  change  note- 
books, the  teacher  taking  the  minerals  and  naming  them 
in  order  from  No.  1  up,  while  the  pupils  check  the  mis- 
takes. 

Should  time  permit,  it  would  be  well  for  the  speci- 
mens to  be  again  given  to  the  class,  that  each  may  cor- 
rect his  errors. 

Material  put  away. — Let  willing  and  trusted  hands 
sort  the  1,500  mixed  specimens,  picking  out  the  soft  ones 
first,  and,  as  thirty  of  a  kind  are  found,  bring  to  the 
teacher  for  inspection  and  return  to  the  store  box. 

Fragmentft— Save  for  blowpipe  work  in  the  future. 


270  SYSTEMATIC  SCIENCE  TEACHING. 

Blowpipes,  streak  plates,  How  to  Study,  etc.,  should 
also  be  put  away  in  labeled  boxes. 

Field  Work  and  Pupils'  Collections.— It  is  all  impor- 
tant that  the  connection  between  these  indoor  studies  and 
nature  now  be  made.  Have  the  class  hunt  up  old  hammers 
and  hatchets  (a  ''  lathing  "  hatchet  is  excellent),  and,  led 
by  the  teacher  or  some  competent  person,  explore  quar- 
ries, crack  bowlders,  visit  mines,  stone  yards,  marble 
works,  etc. 

The  specimens  thus  gathered,  with  such  as  the  pupil 
may  have  acquired  in  other  ways,  should  then  be  brought 
to  some  place,  tickets  gummed  on  (see  Step  XIV),  and 
each  set  neatly  numbered  in  ink.  Opposite  corresponding 
numbers  in  the  notebook  should  now  be  placed  (in  pencil) 
what  he  or  she  determines  it  to  be.  Then,  the  pupil  hav- 
ing done  all  he  can,  let  the  teacher  revise  his  list,  leav- 
ing blanks  for  all  unknown,  and  in  case  of  rocks  naming 
them  only  as  containing  such  and  such  minerals. 

This  will  test  the  teacher ;  but  I  have  never  found  a 
frank  "  I  do  not  know  "  to  weaken  my  influence  in  the 
least.  In  fact,  well-taught  pupils  are  a  little  distrustful  of 
the  teacher  who  knows  everything  and  can  learn  no  more. 

A  gift  of  some  admired  or  unobtainable  specimens  will 
send  all  home  happy,  and  be  money  well  spent. 

In  conclusion  I  have  nothing  to  say,  as  such  work 
will  speak  for  itself. 

Next  Step  XLIII— Coins. 


STEP  XXXVIII.— ANIMALS. 
The  Life  Histories  of  Some  Types. 

Object. — A  general  survey  of  animals  has  been  had  in 
Steps  V,  IX,  and  XI.  The  foundations  of  a  knowledge 
of  external  organs  and  their  functions  has  been  laid  in 
Steps  XIX  and  XXVII,  and  the  inter-relations  of  animals 
and  their  environments,  with  something  of  geographical 
distribution,  considered  in  Step  XXIX. 

For  the  student  or  class  which  has  done  all  of  this 
work  in  a  thorough  and  consecutive  manner  the  next  two 
steps  may  well  be  omitted,  and  the  subject  of  classifica- 
tion taken  up  at  once. 

Experience  has,  however,  shown  that  new  pupils  com- 
ing into  a  class,  and  irregularities  of  attendance  due  to 
the  various  accidents  of  health,  etc.,  will  render  a  review 
highly  advantageous. 

This  I  have  cast  in  a  shape  which  will  have  the  fresh- 
ness of  a  new  subject,  and  still  include  the  essentials  of  a 
review  of  former  studies. 

Time. — Spring  is  the  best  to  secure  material,  and  in 
graded  work  other  classes  will  be  using  the  same  material 
about  this  time.  There  will  be  about  forty  drawings  to 
make,  but  many  are  small  and  easily  done,  so  that  twenty 
to  twenty-five  lessons  of  thirty  minutes  each  will  easily 
cover  the  work.  If,  as  is  hoped,  it  can  be  made  the  basis 
of  the  drawing  lessons,  the  step  will  really  take  but  very 
little  extra  time. 

The  work  of  this  step  and  that  of  the  preceding  (min- 
erals) may  easily  be  interwoven,  and  the  drawings  be  be- 

271 


272  SYSTEMATIC  SCIENCE  TEACHING. 

gun  as  early  in  the  spring*  as  material  can  be  procured, 
taking  whatever  comes,  without  regard  to  the  order,  and 
resuming  the  mineral  work  in  case  animal  material  fails 
or  delay  is  needed  to  watch  and  record  the  development 
of  eggs,  larvae,  etc. 

Material. — Must  be  mostly  fresh,  and  suggestions  as  to 
where  and  how  to  procure  it  will  be  found  in  previous 
steps  of  animal  work. 

Each  student  will  need  a  drawing  book  or  sheets  of 
drawing  paper  about  8  x  10  inches  in  size,  and  a  good  pen- 
cil. Some  water  color  can  be  used  to  excellent  advantage. 
Use  erasers  sparingly,  if  at  all. 

I  have  found  it  possible  to  secure  a  sentiment  in  a 
class  so  opposed  to  erasures  as  to  result  in  that  careful  ex- 
amination of  the  object  and  exact  and  painstaking  repro- 
duction on  paper  which  is  so  desirable. 

Preparation. — A  teacher  should  have  made  all  the 
drawings  from  life  and  thoroughly  studied  the  life  his- 
tory in  each  case  before  attempting  to  give  the  lesson, 
and  this  can  best  be  done  a  year  in  advance.  Arrange- 
ments for  material  must  be  carefully  made. 

The  Lessons. 

1.  Have  the  pupils  head  each  page  of  their  drawing 
books  with  the  name  of  the  animal  whose  life  history  is 
to  be  more  or  less  completely  illustrated  on  that  page — 
e.  g.,  ''  Frog :  eggs,  tadpoles,  adult."  This  will  permit  the 
drawings  to  be  neatly  arranged  on  the  page,  even  though 
made  at  different  times,  and  also  enable  a  pupil  to  keep 
at  work,  though  the  specimens  available  are  not  in  the 
exact  sequence  of  the  list  to  follow,  which  is  according  to 
Dr.  Emil  Selenka's  classification. 

2.  Taking  the  first  available  material,  or  such  as  will 
not  keep  (eggs,  larvae,  etc.),  let  the  class  go  to  work  at  the 
careful  study  and — to  aid  in  this— illustration  of  the  life 
histories  of  the  selected  types.    Morse's  First  Book  in 


ANIMALS.  273 

Zoology  *  is  a  model  for  the  kind  of  drawings  to  make, 
and  for  the  spirit  in  which  the  work  should  be  done. 

Amoeba.— Draw  from  personal  observation  under  the 
microscope,  if  possible ;  otherwise  copy  from  some  book. 
Morse's  First  Book  in  Zoology  or  the  Eiverside  Natural 
History  will  supply  cuts  for  any  copy  which  will  have 
to  be  made. 

Earthworm. — Place  on  a  wet  dish  and  draw  from  life. 
Eggs  and  young  can  be  copied. 

Starfish. — Draw  from  life,  or  dried  specimen,  both  up- 
per and  under  sides,  and  copy  a  cut  of  one  arm  with  the 
tube  feet  extended. 

Crayfish. — Place  a  live  specimen  in  a  shallow  dish  of 
water  and  sketch  the  eggs,  young,  and  adult.  Keep  care- 
ful data  regarding  the  tivie  required  to  hatch  the  eggs, 
when  young  forsake  the  mother,  etc. 

Spider. — Sketch  a  cocoon  of  eggs,  the  young  magni- 
fied, and  the  adult  with  her  web.  The  latter  may  have  to 
be  copied  from  Morse. 

Squash  Bug. — Sketch  eggs  on  squash  leaf,  larva,  pupa, 
and  imago. 

Butterfly. — Sketch  eggs  on  cabbage  leaf  (or  food  plant), 
the  caterpillar  after  each  molt,  pupa,  and  when  hatched, 
the  imago.  The  latter  should  be  sketched  with  the  left 
wings  upside  down,  and,  to  show  this,  slightly  detached 
from  the  body.  If  color  is  used  after  the  outline  has  been 
drawn  with  a  fine-pointed  pencil  it  will  greatly  add  to 
the  scientific  value  and  attractiveness  of  the  sketch. 

It  is  also  well  to  note  the  time  in  days  (or  hours,  if 
short)  between  one  form  and  another  from  the  first  tiny 
caterpillar  to  the  imago. 

Clam. — Draw  the  outside  and  inside  of  one  valve ;  also 
of  the  animal,  if  it  can  be  had.  The  latter  can  be  copied 
from  some  good  work  on  zoology. 

*  D.  Appleton  and  Company. 
19 


274  SYSTEMATIC  SCIENCE  TEACHING. 

Water  Snail  (operculated,  gill  breather). — Place  in  a 
dish  of  water  for  study,  and  draw  eggs,  young  snail,  and 
adult  (when  the  head  is  out)  with  shell  and  operculum  on 
its  back. 

Land  Snail  (air  breather). — Eggs,  young,  and  adult 
when  head  is  out  of  the  shell.  Eggs  and  young  will 
probably  have  to  be  copied  from  Morse. 

Fish. — Draw  from  life,  or,  if  dead,  take  a  thin  board, 
and,  laying  the  fish  upon  it,  draw  the  fins  into  position 
with  pins  and  fasten.  Slightly  incline  the  board  on 
edge,  and  the  fish  will  be  in  excellent  position  to  sketch 
in  outline.  Pay  careful  attention  to  the  exact  position 
and  number  of  spines  and  soft  rays  in  the  fins,  the  posi- 
tion of  the  mouth,  kind  of  gill  covers,  etc.  Also  detach 
a  scale  and  make  an  enlarged  drawing  of  its  shape 
and  structure.  Copy  eggs  and  fry  from  some  work  on 
zoology. 

Frog. — Sketch  newly  gathered  egg  cluster,  and  make 
other  drawings,  with  the  dates  and  time,  as  often  as 
changes  appear  in  the  eggs.  Draw  tadpole  when  hatched 
(magnified,  if  possible),  and  draw  as  often  as  any  change 
appears  till  the  small  but  perfect  frog  has  developed. 
Would  consult  (but  not  copy)  the  sketches  in  some  good 
work  on  zoology. 

Snake. — Draw  eggs,  young,  and  adult.  Be  exact  about 
the  number  of  rows  of  scales  over  the  back,  and  the  shape 
of  each. 

Hen. — Sketch  the  egg  and  copy  the  internal  structure 
of  the  same  from  Orton's  Comparative  Zoology.  Sketch 
the  young  chick  from  life  ;  also  the  hen. 

This  completes  the  list  it  has  been  found  best  to  use. 
Interspersed  with  the  drawing  exercises  should  be  such 
discussions  of  the  different  animals  as  the  class  may  need 
to  bring  out  the  salient  characteristics  of  each  type.  Some 
of  the  material  can  most  easily  be  had  in  the  fall  term 
(e.  g.,  butterfly,  spider,  squash  bug),  and  in  such  case  I 


ANIMALS.  275 

would  delay  the  study  till  then,  or  let  the  pupil  do  it  in 
vacation. 

The  next  step — XXXIX — is  only  inserted  to  give  op- 
portunity to  complete  the  autumn  work  of  this,  and  may 
otherwise  be  omitted. 


STEP  XXXIX.— ANIMALS. 
The  Life  I^stories  of  Some  Types— (Concluded). 

Object— The  same  as  Step  XXXVIII,  which  see. 

Time,  etc.,  autumn.  This  step  is  introduced  at  this 
time  of  the  year  in  order  that  such  desirable  studies  of 
types  as  could  not  be  made  in  the  spring  may  now  be 
taken. 

Abundant  material  can  easily  be  found  in  the  autumn 
for  any  desired  number  of  lessons,  especially  on  insects ; 
but  I  would  advise  saving  the  time  for  the  other  science 
work  of  the  year,  and,  having  pushed  the  outline  of  Step 
XXXVIII  to  a  conclusion,  stop. 

The  work  of  this  and  the  next  step  can  well  go  on  at 
the  same  time ;  perhaps  best  so.  • 

The  next  step  is  XLIX — Animal  Groups. 
276 


STEP  XL.— FRUITS  REVIEWED. 

Object  of  this  Step. — Fruits  were  looked  at  and  sorted 
in  Step  I;  studied  more  carefully  and  grouped  in  Step 
XVIII.  One  fruit  was  examined  in  detail  in  the  Morn- 
ing-Glory, Step  XXIII,  and  the  relation  to  distribution 
of  the  seed  and  uses  considered  in  Steps  XXVIII  and 
XXXIV. 

Four  years  will  now  have  elapsed  since  Step  XVIII 
was  taken;  many  new  pupils  will  have  come  into  the 
classes  since  then,  and  now  it  may  be  advisable  to  review 
the  subject  along  the  lines  given  in  Steps  XVIII,  XXVIII, 
and  XXXIV.    The  stress  should  be  laid  on  the  following : 

(a)  Origin  (a  ripened  pistil  or  pistils  with  adhering 
parts). 

(b)  Protection  while  growing  (green,  sour,  bitter,  etc. ; 
see  Step  XXVIII). 

(c)  Variations  in  form  and  structure  (see  Step  XVIII). 

(d)  Modes  of  opening  (see  Step  XVIII). 

(e)  Methods  for  self-distribution  of  the  seeds  (see 
Step  XXXIV). 

(/)  Lnres  to  secure  aid  in  seed  distribution  (see 
Steps  XXVIII  and  XXXIV). 

Ig)  Modes  of  compelling  aid  in  distribution  (see  Steps 
XXVIII  and  XXXIV). 

Time  used  should  not  exceed  twenty  half-hour  lessons 
in  the  autumn. 

Material — The  same  as  used  in  previous  steps  and  in 
graded  school  work.  That  of  one  room  can  frequently  be 
used  again  in  some  other. 

277. 


278  SYSTEMATIC  SCIENCE  TEACHING. 

Preparation  of  the  Teacher.— Read  the  steps  referred 
to  above  under  "Object,"  and  arrange  such  work  as  each 
class  may  require. 

Drawing  and  color  work  will  find  abundant  material 
in  connection  with  this  step,  and  reduce  the  time  needed. 
With  the  previous  training  the  science  work  has  given 
and  the  increased  age  and  ability  of  expression  by  word, 
pencil,  or  brush,  this  should  prove  a  very  attractive  and 
profitable  piece  of  work.  Make  thorough  preparation, 
and  push  the  work  energetically  to  a  conclusion. 

Material  put  away  (see  Step  XVIII). 

The  next  step  in  plant  work  is  Corn  and  Beans — Clas- 
sification, Step  XLI, 


STEP  XLI.-CORN  AND  BEANS.  * 

Object. — The  basis  of  plant  classification. 

The  unconscious  comparing  through  the  sorting  of 
the  earlier  steps  has  been  made  more  exact  through  the 
studies  of  metals  and  minerals. 

The  culminating  work  in  developing  the  powers  of 
exact  observation  and  concise  description  begins  with 
this  step,  and  is  continued  through  Steps  XLV,  XLVI, 
and  XLIX. 

Familiar  now  with  many  plants  and  with  some  in- 
sight into  the  meaning  of  their  variations  of  form  and 
structure,  the  pupil  occupies  a  vantage  ground  from 
which  to  consider  their  relationship  with  each  other. 
This  new  view  will  also  make  an  effective  preparation  for 
what  is  to  follow. 

The  Time. — About  twenty  lessons  in  the  early  autumn. 
Should  it  be  deemed  wise  to  give  Steps  XXXIX  and  XL, 
the  frosts  may  destroy  the  flowers  for  XL  unless  taken 
in  advance,  and  the  work  must  be  skillfully  planned  and 
XL  may  have  to  be  delayed.  Much  of  this  step  could  go 
on  while  other  work  was  in  hand,  taking  a  lesson  in  this 
whenever  material  was  ready. 

Material. — Little  is  needed.  A  handful  each  of  corn, 
onions,  oats,  wheat,  and  rye  for  the  monocotyledons,  and 
beans,  peas,  morning-glory,  melon,  and  turnip  or  radish 
seed  for  the  dicotyledons.  Provision  must  also  be  made 
for  flowers  with  parts  in  threes  and  fives,  and  cannas  and 
gladioli  should  be  planted  in  the  spring  for  the  threes, 
and  nasturtium,  petunia,  and  morning-glory  for  the  fives. 

279 


280  SYSTEMATIC  SCIENCE  TEACHING. 

The  preparation  of  the  teacher  is  partly  indicated 
above.  Go  over  the  step  in  advance,  decide  just  what  to 
do  and  when,  locate  and  arrange  for  material,  and  then 
piLsh  the  work  steadily  to  a  conclusion. 

^  Outline  to  be  Developed. 

A.  How  do  the  planted  seeds  emerge  ? 

B.  How  many  cotyledons  has  each  ?  "What  other 
parts  ? 

C  What  kind  of  roots,  multiple  or  tap  ? 

D.  The  stem,  as  to  bark,  wood,  pith,  and  branching. 

E.  The  leaves,  as  to  veining,  simple  or  compound,  gen- 
eral outline,  tip,  margin,  base,  petiole,  and  arrangement. 

F.  Flowers,  parts  in  threes  or  fives. 

G.  Seed,  all  germ  (exalbuminous),  or  with  food  (albu- 
minous). 

H.  Grouping  of  all  the  plants  in  two  sets,  under  corn 
and  beans. 

The  Lessons. 

1.  Plant  two  or  three  seeds  of  each  sort  (see  Material) 
for  each  member  of  the  class.  Boxes  holding  two  or 
three  inches  of  clean  sand  are  best,  as  the  plants  will  be 
neater  to  handle.  Eecord  the  date  of  planting,  the  high- 
est and  lowest  temperature  each  day,  and,  keeping  the 
ground  well  watered,  record  the  hours  before  they  first 
show  through  the  covering  of  sand. 

If  planted  some  Friday  afternoon,  this  will  be  com- 
pleted before  the  end  of  the  next  week. 

2.  Let  the  class  take  notebooks  (about  10  x  16  cm.  in 
size,  and  opening  at  the  end)  and  head  the  top  of  succes- 
sive double  pages  with  the  questions  of  the  Outline. 

On  the  first  page  record  the  date  of  planting  and  tem- 
peratures, list  of  seeds,  and  after  each  the  hours  for  it  to 
come  up,  and  whether  it  pushed  out  (corn)  or  backed  out 


CORN  AND  BEANS. 


281 


(bean).    Press  a  specimen  of  each  to  mount  and  label  (if 
the  time  permits  and  practice  in  such  work  is  desired). 

3.  While  the  seeds  are  coming  up,  study  question  D. 
Give  the  class  the  sections  of  stems  from  Step  XIII  (to 
represent  the  way  a  bean  would  grow  if  it  lived  several 
years)  and  pieces  of  cornstalk.  When  complete,  the 
proper  page  in  the  notebook  will  be  thus : 


Corn. 

Resemblances. 

Bean. 

(Sketch  cross  section 
of  cornstalk  here.) 

Cylindrical  stems. 
Hard  outside. 
Pith. 
Wood. 

Differences. 

(A  sketch  section  of 
oak  stem  here  will 
do  for  the  bean.) 

Smooth,  green  skin. . 
In  threads 

Bark 

Rough,  dark  bark. 
In  rings. 

Wood 

None 

Radiating  lines  . . . 
Pith 

Many. 

Much     

A  little  in  the  center. 

Unbranched 

Branching 

Much  branched. 

In  all  the  notes  keep  "  corn  "  and  its  allies  on  the  left 
side  of  the  page,  and  "  bean  "  and  allies  on  the  right. 
Under  "  resemblances  "  place  (in  the  middle  of  the  page) 
all  the  points  in  which  the  plants  are  alike.  In  the  blank 
space  to  either  hand  make  such  drawings  as  will  illustrate. 
On  the  lower  page  place  "  differences,"  and  under  the  word 
all  the  points  observed,  extending  each  point  as  may  be 
appropriate  to  the  heading  (corn  or  bean)  it  falls  under. 
After  the  pupils  have  individually  and  unassisted  written 
all  they  can  observe,  and  made  their  drawings,  have  them 
compare  notes  by  reading  items  in  turn,  that  those  who 
have  omitted  points  may  add  them  and  the  mistakes  be 
corrected. 

4.  When  the  seeds  are  all  up,  dig  a  well-developed 
seedling  of  corn  and  one  of  bean  for  each  pupil  to  study. 


282  SYSTEMATIC  SCIENCE  TEACHING. 

Make  sketches  under  B  and  C,  write  the  points  in  which 
they  are  alike  under  "resemblances,"  and  those  in  which 
they  differ  under  "  differences."  When  this  is  done,  give 
them  one  after  another  the  other  six  seedlings  to  decide 
which  of  the  two  previous  plants  it  most  nearly  resem- 
bles, and  record  the  name  on  the  proper  side  of  the  page. 
Press  the  specimens. 

A  little  diflBlculty  will  here  occur,  which  I  have  pur- 
posely introduced.  The  pea  seed  remains  in  the  ground 
(like  the  corn),  and  the  onion  "  backs  out "  doubled  over 
(as  the  bean).  Explain  here  that  no  rule  is  without  ex- 
ceptions, and  that  in  grouping  we  must  go  by  the  genei^al 
and  greatest  number  of  characteristics.  Hence  as  the 
onion  is  cornlike  in  everything  else,  it  is  allied  to  it,  and 
the  pea  is  allied  to  the  bean. 

5.  Leaves. — From  the  garden  and  cornfield  get  small 
sprigs  (stem  and  leaf)  of  corn  and  bean  plants.  Let  the 
class  sketch  and  write  notes  (see  E). 

6.  When  the  ideas  of  parallel- veined  and  net- veined 
leaves  are  learned  give  a  number  of  mixed  sprigs  of  leaves 
(see  Step  X)  illustrating  the  variations  suggested  in  E. 

Let  these  be  sorted  into  piles  of  parallel- veined  and  net- 
veined  leaves,  and  from  these  add  to  and  verify  the  resem- 
blances and  differences  before  written.  Press  and  mount 
cards  of  leaves  to  illustrate  what  has  been  written. 

When  the  seedlings  in  the  boxes  have  grown,  observe 
their  leaves  in  the  same  way. 

7.  Flowers. — Choose  the  most  available  flower  hav- 
ing its  parts  in  threes  (canna  or  gladiolus),  and  also  one 
with  parts  in  fives  (pea,  pink,  or  morning-glory).  Let  the 
class  write  the  resemblances,  sketch  so  as  to  show  the 
number  of  parts,  and  write  the  differences.  Then  give 
several  other  flowers  to  examine  and  range  under  threes 
or  fives  (see  F). 

8.  Seed. — Soak  some  of  the  kinds  of  seeds  planted  for 
a  day.    Give  a  large  grain  of  corn  and  a  bean  to  exam- 


CORN  AND  BEANS.  283 

ine,  sketch,  and  write  about.  Then  examine  the  others 
and  decide  which  they  are  most  like  (see  G).  Here,  again, 
the  albuminous  seed  of  the  morning-glory  will  teach  cau- 
tion in  generalizing. 

9.  Bring  an  entire  com  plant  and  also  a  bean  plant  be- 
fore the  class.  In  what  respects  are  they  alike  f  Record 
under  "resemblances."  Under  "differences,"  as  before, 
note  all  the  points  unlike.  This  will  review  the  other 
work,  and  the  class  can  now  generalize  and  group. 

10.  (H.)  Now  place  "  Corn  "  at  the  head  of  one  page 
and  "  Bean  "  at  the  head  of  the  other,  and  by  memory  and 
notes  decide  under  which  the  plants  raised  or  studied  be- 
long. 

11.  Qnestion  as  follows  to  fix  the  associations : 

A  plant  has  two  seed  leaves  (cotyledons).  What  is 
probable  as  to  its  root  ?  (tap).  Stem  ?  (bark,  wood  in 
rings,  pith  distinct,  branched).  Leaves  ?  (net-veined  and 
varying  as  to  parts,  etc.).  Flowers  ?  (in  fives).  Seed  ? 
(without  albumen). 

A  plant  has  a  multiple  root.  What  is  probable  as  to 
its  cotyledons  ?  (one).  Mode  of  germination  ?  (pushes 
up).  Stem  ?  (no  bark,  threads  of  wood  in  abundant  pith, 
and  unbranched).  Leaves  ?  (alternate,  sessile,  simple, 
parallel- veined,  and  entire).  Flowers  ?  (in  threes).  Seed  ? 
(albumen  around  the  germ). 

Thus  proceed  through  all  the  points  noticed. 

12.  Have  the  class  bring  parts  of  plants,  and  the  teacher 
distribute  for  the  different  pupils  to  decide  where  they 
should  be  grouped,  as  exogens  or  endogens. 

Whenever  the  class  is  keenly  alive  to  such  grouping, 
and  can  be  relied  upon  to  locate  a  plant  properly  by  its 
general  characters,  drop  the  work  and  take  the  next  step. 

The  next  step  in  plant  work  is  Plant  Families,  Step 
XLV. 


STEP  XLII.— THE  EARLY  HISTORY  OF  THE  EARTH. 

Object. — To  review  and  expand  the  work  of  Step 
XXXV,  and  in  attempting  to  picture  some  of  the  stages 
in  the  life  history  of  our  own  earth,  prepare  for  the  follow- 
ing steps ;  above  all,  to  exercise  the  powers  of  concentrated 
and  imaginative  thought.  The  ability  to  use  the  imagi- 
nation in  foreseeing  each  step  in  any  problem  is  of  the 
highest  value,  and  its  cultivation  the  main  object  of  this 
study. 

Time. — Will  be  about  twenty-five  lessons  of  thirty 
minutes  each  during  the  winter  term. 

Material  and  Supplies.— The  star  lanterns,  charts  of 
the  heavens,  telescope,  etc.,  as  indicated  in  the  last  steps 
of  star  work.  Ample  notebooks  for  the  full  notes  this 
non-experimental  subject  will  require.  These  should  be 
frequently  examined  with  care,  that  proper  habits  may 
be  formed. 

Preparation  of  the  Teacher.— Must  be  wide  and  thor- 
ough for  the  peculiar  demands  of  the  work  indicated. 

Get  the  connection  with  the  preceding  step,  and  also 
Step  XL VII.  Then  see  the  relation  of  these  to  those  on 
rocks  (Steps  XLIV  and  XL VIII).  Read  Ecce  Coelum 
(Burr).  Master  the  theory  of  Laplace  as  fully  as  possible. 
This  will  be  found  in  its  more  recent  form  in  Young's 
General  Astronomy,  Todd's  New  Astronomy,  Ball's  Time 
and  Tide,  and  A  Glimpse  through  the  Corridors  of  Time, 
Appletons'  Popular  Science  Monthly,  vol.  xx,  or  Nature, 
vol.  xxv. 


THE  EARLY  HISTORY  OF  THE  EARTH.      285 

The  Lessons. 

Owing-  to  the  peculiar  nature  of  the  end  in  view,  suc- 
cess will  depend  upon  the  knowledge  and  skill  of  each 
teacher,  and  individuality  must  have  full  play.  Hence 
it  is  deemed  best  to  simply  indicate  the  topics  and  order 
of  their  presentation  which  have  proved  successful. 

The  following  points  should  be  put  to  the  class  in  the 
form  of  questions,  and  discussed  till  an  answer  is  agreed 
upon : 

1.  Give  an  oral  quiz  on  the  outline  of  Step  XXXV. 
This  will  refresh  the  subject  and  aid  any  new  pupils. 

2.  Explain  the  meaning  of  hypothesis,  and  lead  the 
class  to  see  how  helpful  such  tentative  forecasts  are  if 
constantly  held  open  to  revision,  and  that  in  the  attempt 
they  are  about  to  make  of  imagining  how  the  earth  came 
to  its  present  condition  much  may  be  shown  by  future 
discovery  to  be  very  incorrect. 

3.  The  sun,  all  his  planets,  and  their  moons  were  once 
a  nebula  (Todd,  p.  466  ;  Young,  p.  516). 

4.  Through  cooling,  condensation,  and  rapid  revolu- 
tion portions  became  separated,  among  which  was  our 
earth,  and  from  her  again  separated  the  moon  (Young, 
pp.  516-518,  and  Todd,  p.  467). 

(Illustrate  by  the  bursting  of  huge  grindstones  or  fly- 
wheels, etc.,  Step  XXX.) 

5.  The  less  volatile  substances  (sand,  lime,  iron,  etc.) 
would'  first  condense  to  a  liquid  sphere. 

(Illustrate  by  the  "  spit "  which  drops  so  quickly  from 
the  flame  of  a  steel  converter  (Step  XXXV,  §  17.) 

6.  The  more  easily  vaporized  water,  carbon,  sulphur, 
lead,  etc.,  would  remain,  covering  this  liquid  sphere  with 
a  dense  envelope  of  gases  and  vapors. 

7.  These  heated  vapors  would 

(a)  Rise  to  higher  altitudes  (convection). 

(b)  Radiate  heat  into  space  and  condense  to  thick 
clouds  (as  the  smoke  of  furnaces,  steam  of  locomotives. 


286  SYSTEMATIC  SCIENCE  TEACHING. 

or  "  thunder  heads  "  of  summer ;  Tyndall's  Heat,  pp.  408, 
409). 

(c)  Also  cool  through  the  expansion  due  to  diminish- 
ing pressure  at  great  heights — steam  from  boiler ;  fog  in 
bell  jar  of  an  exhausting  air  pump  (Tyndall,  pp.  45-47) ; 
the  cold  exhaust  of  a  compressed-air  motor ;  air  from  a 
bellows  through  a  narrow  opening,  etc.  (Tyndall,  pp.  27, 
28). 

(d)  These  dense  masses  of  vapor  would  cause  complete 
darkness  except  for  light  from  the  heated  sphere  within. 
(Remind  of  cloudy  days,  smoke  from  a  city,  etc.,  and  im- 
agine what  would  be  the  result  if  all  the  water  and  car- 
bon were  in  the  air.)  Might  the  sun,  moon,  and  stars  be 
shining  and  still  no  light  come  through  ? 

8.  The  condensed  vapors  would  be  continually  fall- 
ing in  acid  rain,  to  be  revaporized  and  rise  again.  (Re- 
mind of  the  great  capacity  of  water  for  heat,  and  discuss 
the  effects  of  this  on  the  cooling  of  the  central  sphere.) 
How  would  the  dense  envelope  of  gases  and  vapors, 
particularly  HaO,  SO2,  and  COa,  surrounding  the  globe 
affect  its  cooling  ?  (See  Tyndall,  pp.  365-368,  404-416, 
etc.) 

9.  As  heat  was  lost  throup-h  radiation  and  evapora- 
tion the  fluid  globe  began  to  solidify. 

When  might  this  first  begin  ? 

Is  solid  rock  lighter,  or  heavier,  than  fused  ?  (Ice,  cast 
iron,  and  other  crystalline  solids  float  in  fusing  or  solidi- 
fying.) 

10.  A  crust  covered  the  earth  cool  enough  for  water  to 
remain  upon  it.  Day  began  to  be  distinguishable  from 
night.     Could  sun  or  moon  be  seen  ? 

11.  A  universal  sea  of  hot  water  loaded  with  mineral 
substances  enveloped  the  globe. 

12.  Further  cooling  and  the  contracting  crust  wrinkled 
into  ridges  (land)  and  hollows  (seas).  Volcanic  outbursts 
frequent  and  violent.    (See  Judd,  Volcanoes,  p.  260.) 


THE  EARLY  HISTORY  OP   THE   EARTH.      287 

13.  Torrential  and  corrosive  rains  feU  on  the  emerg- 
ing land,  sweeping  it  in  mud,  etc.,  back  into  the  sea. 

14.  Tremendous  tides  swept  the  shores,  aiding  in  ero- 
sion, and  transported  the  detritus  into  deep  water  (Time 
and  Tide,  pp.  144-154). 

15.  Vast  beds  of  sediment  accumulated  off  the  coasts. 

16.  Under  these  vast  blankets  of  sediment  the  internal 
heat  softened  and  weakened  the  ocean  bed.  (Diagram  on 
the  blackboard.    See  Le  Conte's  Geology,  pp.  252-260.) 

17.  Heat  from  below  also  penetrated  the  beds  of  sedi- 
ment, causing  semif  usion,  crystallization,  and  consequent 
expansion.  (Water  to  snowflakes  ;  ice  expands ;  castings 
of  iron  and  type  metal  are  "  sharp  " ;  Step  XX,  §§7,  8.) 

18.  The  enormous  lateral  pressure  of  the  shrinking 
arch  of  the  earth's  crust  mashed  this  softened  mass  into 
slowly  rising  additions  to  the  land  area. 

19.  While  this  (11  to  18)  was  going  on,  the  acids  and 
minerals  dissolved  in  the  ocean  waters  were  uniting  to 
form  solids,  which  settled,  and  the  waters  became  purer. 

20.  As  the  ocean  and  land  cooled,  more  and  more  of 
the  vapors  surrounding  the  forming  earth  condensed,  and 
the  atmosphere  cleared.  Day  and  night  became  more 
marked,  and  at  last  the  sun  and  moon  could  be  seen. 

21.  The  land  was  continually  being  worn  away  by 
the  rain,  and  soil  was  gathering  in  the  valleys. 

^2.  When  the  ocean  was  pure  enough,  life  began,  and 
as  the  atmosphere  cleared  it  was  transferred  to  land. 

23.  Atmosphere,  ocean,  and  life  now  worked  together 
to  prepare  for  man. 

Review  by  (1)  each  pupil  telling  what  has  particu- 
larly interested  him ;  (2)  class  ask  questions  on  points 
needing  more  explanation;  (3)  teacher  completes  what 
may  have  been  omitted  by  questions. 

Meet  evenings  for  star  work.  The  pupils  will  now  be 
old  enough  to  enjoy  and  profit  by  the  use  of  such  star 
lanterns,  maps,  telescopes,  etc.,  as  they  can  gather. 


288  SYSTEMATIC  SCIENCE  TEACHING. 

Ways  which  have  proved  successful  in  the  past  may 
be  suggestive  to  others. 

A  Star  Party. — Provide  blank  calling  cards  or  pieces 
of  heavy  drawing  paper,  enough  for  all  who  are  invited 
for  some  moonless  night.  Lay  tracing  paper  over  a  star 
map  or  the  side  of  a  star  lantern,  and  mark  the  distin- 
guishing stars  of  half  as  many  constellations  as  you  have 
cards,  and  indicate  ''  up  "  by  an  arrow  tip.  Adapt  your 
choice  to  the  age  and  character  of  your  guests,  as  well  as 
to  the  time  of  the  year.  Lay  these  tracings  on  the  cards, 
and  prick  through  each  star  into  the  card,  doing  a  pair 
of  each.  Now  gum  gilt  paper,  or  use  gilt  paint,  to  mark 
the  stars,  using  dots  for  the  smallest,  and  3,  4,  6,  and  8 
points  from  a  dot  for  the  succeeding  sizes  up  to  the  first 
magnitude.  Now  find  appropriate  quotations  (see  Bai- 
ley's Astral  Lantern  or  Primary  Astronomy  ;  Chambers's 
Story  of  the  Stars ;  Serviss ;  the  Bible ;  and  Gore's 
Scenery  of  the  Heavens)  and  place  half  on  each  of  the 
pairs  of  cards,  indicating  the  break  in  the  quotation  by 
dots  (.  .  .)  on  each  card. 

For  children,  indicate  up  by  an  arrow  point,  but  omit 
this  for  more  experienced  youths.  In  case  these  "par- 
ties "  are  repeated,  or  it  is  intended  to  make  use  of  tele- 
scopes, add  nebulae,  double  stars,  etc.,  to  the  cards. 

As  the  guests  arrive  give  each  a  card,  and  say  that  the 
mate  is  to  be  found  in  some  one  else's  hand,  and  that  both 
together  are  to  find  the  constellatioQ.  If  it  is  desired  to 
make  the  matter  competitive,  let  each  couple  return  their 
cards  as  quickly  as  the  constellation  can  be  named,  and 
get  others,  keeping  a  record  of  how  many  each  names. 

Celebrate  astronomical  events,  eclipses,  occultations, 
etc. 

For  a  "  Mars  opposition  social  "  a  two-foot  paper  globe 
(sun)  was  made  from  hoops,  and  across  the  fields  or  in 
house  windows  lanterns  of  appropriate  colors  were  placed 
to  represent  the  planets  at  distances  of  one  foot  for  each 


THE  EARLY  HISTORY  OF  THE  EARTH.      289 

400,000  miles,  the  sun,  earth,  and  Mars  in  line.  In  the 
house  a  fourteen-foot  strip  of  board  carried  the  pins  and 
balls  of  Step  XXIV  at  two  mm.  to  each  1,000,000  miles. 

Photographs  of  Mars,  astronomical  literature,  maps, 
etc.,  were  laid  on  tables,  and  after  a  short  address  on  the 
occasion,  music  ("  Beautiful  Star  in  Heaven  so  Bright," 
"  Stars  of  the  Summer  Night,"  etc.)  was  provided. 

Star  clubs  might  be  made  very  popular.  Vary  the 
requirem.ents  to  suit  those  it  is  desired  to  interest,  have  suit- 
able papers  at  times,  and  stimulate  attendance  by  "  hon- 
orable mention  "  or  prizes  for  those  having  the  most  con- 
stellations or  single  stars  learned,  double  stars  resolved, 
iiebulye  located,  etc. 

Next  Step  XLVII— Other  Systems  than  Ours. 


STEP  XLTII.— COINS  AND  COINAGE. 

Object. — To  keep  up  the  thread  of  work  begun  in  Man 
at  Home,  and  increase  the  knowledge  of  these  interesting 
records  of  the  progress  of  the  human  race.  The  relation 
of  this  work  to  history  and  geography  may  also  prove 
very  helpful,  and  the  two  should  go  hand  in  hand. 

Time  required  will  depend  on  the  enthusiasm  of  the 
instructor,  but  should  not  exceed  twenty  lessons  of  sci- 
ence time. 

Material.— Gather  all  the  coins  which  can  be  procured, 
including  a  full  set  of  our  United  States  money  (bills  in- 
cluded). 

The  lessons,  as  to  method  and  procedure,  must  so  de- 
pend on  the  instructor  and  his  available  material  that 
only  general  suggestions  can  be  made. 

Base  the  work  on  a  study  of  how  coins  have  been 
evolved  by  the  necessities  of  the  race  from  their  primi- 
tive form  to  the  beautiful  work  of  art  seen  to-day. 

"  The  Evolution  of  a  Coin  "  might  well  be  the  motto. 

1.  Study  the  oldest  procurable  coin,  and  in  history 
and  geography  seek  the  reasons  for  its  metal,  device,  etc. 

2.  Take  the  next  oldest  in  the  same  way,  bringing 
out  the  origin  of  each  change  in  metal  or  alloy,  shape, 
weight,  device,  etc.  Continue  this  by  the  best  available 
series  of  types  to  show  how  necessity  has  led  to  one  and 
another  of  the  variations. 

3.  Study  the  processes  of  our  own  mints,  their  loca- 
tion, and  why  there. 

290 


COINS  AND  COINAGE.  291 

4.  By  appropriate  exercises  learn  the  nature  and  value 
of  our  own  coins,  and  the  meaning  of  their  mint  marks 
and  dates,  mottoes,  and  devices. 

5.  Consider  why  paper  money  is  used  ;  its  denomina- 
tion and  manufacture. 

6.  Laws  regarding  the  crime  of  counterfeiting,  and 
what  it  consists  in. 

Notes  should  be  kept  by  the  pupils  of  all  this  work, 
illustrated  by  rubbings  of  both  obverse  and  reverse  of 
eacli  coin  particularly  studied.  This  will  be  facilitated 
by  cutting  a  hole  for  the  coin  in  thick  cardboard,  so  that 
it  will  not  slip  while  the  impression  is  being  made.  This 
will  necessitate  heavy  paper  for  the  notebooks,  or  inter- 
leaving with  drawing  or  thin  and  tough  linen  paper  for 
the  impressions. 

The  competent  teacher  will  find  abundance  of  inspi- 
ration in  this  subject,  and  it  will  open  a  new  vista  to  tiie 
pupil. 

Next  Step  XLIV— Rock  Making. 


STEP  XLIV.— ROCK  MAKING  BY  PHYSICAL 
AGENCIES. 

Object. — So  far,  the  steps  of  both  the  mineral  and  as- 
tronomy lines  have  been  converging  on  this  interesting 
subject,  which  is  to  introduce  pupils  to  the  more  thought- 
ful consideration  of  the  preparation  of  the  earth  for  the 
coming  of  life. 

The  study  of  pebbles,  sharp  stones,  molecules,  and 
minerals  has  been  in  the  direct  line  of  preparation  for 
the  study  of  rocks,  of  which  this  step  is  the  beginning. 

The  lessons  in  astronomy  have  led  up  to  the  grand 
theory  of  Laplace,  and  opened  the  way  to  answer  the 
question  asked  at  the  close  of  the  molecule  study — "  What 
is  another  way,  besides  the  action  of  frost  and  roots,  by 
which  hard  rocks  have  been  reduced  to  fragments  ?" 

The  lessons  in  plant  and  animal  life  have  made  the 
pupil  somewhat  familiar  with  the  life  of  today,  and  so 
to  hold  the  key  which  will  unlock  the  past,  and  help 
understand  something  of  fossils,  coal,  and  lime  rocks. 

As,  aside  from  humanity,  there  is  no  grander  study 
than  astronomy,  so  there  is  no  more  comprehensive  study 
than  geology  (and  its  included  chapter,  physical  geog- 
raphy). Happy  the  pupils  who,  after  due  preparation, 
can  have  wise  instruction  in  this  all-reviewing,  all-em- 
bracing, and  all-harmonizing  subject ! 

Time  needed. — Will  vary  with  the  preparation  of  the 
teacher  and  class;  but  an  average  will  be  about  forty 
lessons  of  thirty  minutes  each. 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.    293 

Material. — In  sorting,  the  child  simply  handled  and 
saw ;  later,  in  Metals  and  Minerals,  the  material  was  se- 
lected for  test  and  experiment ;  now  a  step  in  advance  is 
to  be  taken,  and,  specimen  in  hand  to  observe,  the  pupil 
is  to  exercise  his  reasoning  powers  in  seeking  the  lessons 
each  can  teach.  This  will  often  require  larger  and  heav- 
ier specimens  thaD  in  minerals.  The  following  list  has 
been  carefully  revised,  and  while,  at  the  suggestion  of 
Prof.  O.  W.  Crosby,  some  changes  have  been  made,  it  is 
essentially  the  same  which  has  proved  satisfactory  in 
eight  years'  use. 

These  specimens  are  chosen  in  harmony  with  the  fol- 
lowing brief 

Outline  of  Plan. — l.  Review  the  class  on  the  theory 
of  Laplace  (see  Steps  XXXV  and  XLII). 

2.  Study  volcanic  and  dike  rocks. 

3.  New  ways  of  making  sharp  stones  (No.  2  reduced 
to  fragments). 

4.  Sediments  sorted  and  deposited. 

5.  Solutions  deposited;. chemically  formed  rocks. 

6.  Fragmental  rocks. 

(The  numbered  specimens  are  for  the  pupil;  the 
others  for  the  teacher's  illustration,  although  the  more 
the  pupil  has  the  better.) 

1.  Pumice. 

2.  Cellular  lava. 

3.  Basalt  (compact). 
Basalt  (columnar). 

4.  Trachyte. 

5.  Obsidian. 

G.  Felsite  (porphyritic). 

7.  Diorite  (coarsely  crystalline). 

8.  Granite  (coarsely  crystalline). 

Furnace  slags  (glassy,  cellular,  etc.),  iron  ore,  lime- 
stone, and  coal. 
Rock  with  cracks. 


294  SYSTEMATIC  SCIENCE  TEACHING. 

Stone  split  by  frost. 
Stone  split  by  roots. 
Eock  with  lichens  on  it. 
Rock  scaling  off  on  surface. 
9.  Rock  containing  pyrite. 
Cubes  of  clay. 

10.  Rusted  pyrite. 

11.  Pyrite  in  coal.  ^ 
Bottle  of  effloresced  iron  sulphate. 
Bottle  of  air-slacked  lime. 

Brick  burst  in  burning  from  inclosure  of  lime- 
stone. 
Red  clay. 
Gray  clay. 
Glaciated  bed  rock. 
Glacier  "  tool "  (pebble)  showing  striae. 

12.  Gravel. 

13.  Sand. 

14.  Clay. 

15.  "  Scale  "  from  teakettle  or  boiler. 
Stalactite. 

Stalagmite. 


16. 

Oolite. 

17. 

Limestone. 

18. 

Dolomite. 

19. 

Bog  iron. 

20. 

Siderite. 

21. 

Gypsum  (massive). 

22. 

Rock  salt. 

23. 

Plaster  (from  wall  of  house). 

24. 

Conglomerate. 

25. 

Breccia. 

26. 

Red  sandstone. 

27. 

Gray  sandstone. 

28. 

Shale. 

ROCK  MAKING  BY  PHYSICAL  AGENCIES.     295 

Boxes  to  distribute. — These  may  be  the  cardboard  ones 
used  for  minerals,  but  stronger  ones  of  wood  can  be  easily 
made  by  the  pupils,  and  are  much  better.  (Here  is  a 
chance  for  the  carpenters  of  the  school.) 

Where  to  get.— Many  of  these  can  be  gathered,  espe- 
cially the  illustrative  specimens,  but  the  suggestions 
under  Steps  VIII,  XIV,  and  XXXVII  will  apply  here. 

The  cost  will  be  about  the  same  as  for  an  equal  num- 
ber of  minerals.     Have  them  come  by  freight. 

Store  Boxes. — Large  100-cigar  boxes  will  hold  thirty 
specimens  of  most  of  the  rocks ;  where  one  of  these  will 
not  do,  take  a  starch  box  or  two  cigar  boxes.  For  label- 
ing and  arranging,  see  Minerals  (Step  XXXVII).  All 
rocks  should  have  numbers  on  them  to  correspond  with 
the  list  (see  Step  XIV  for  directions  about  this). 

Notebooks. — Uniform  and  large  enough  for  this  step 
and  the  next  (XL VIII). 

Literature. — Crosby's  How  to  Study  Minerals  and 
Rocks  (75  cents)  will  be  especially  helpful ;  also  Win- 
chelPs  Geological  Excursions  ($1) ;  Shaler's  First  Lessons 
in  Geology  ($1).  For  illustrations  and  reference  I  like 
Dana's  Manual  of  Geology,  last  edition  ($5),  Le  Conte's 
Geology  ($3),  and  Judd  on  Volcanoes  ($1.50).  No  book 
was  ever  more  interesting  to  me  (as  a  boy)  than  Tenney's 
Geology  ($1).  He  was  a  noble  man,  and  although  the 
book  is  out  of  date,  the  spirit  of  it  is  delightful.  Have 
several  copies  for  the  class  to  read,  or  give  as  prizes. 

Preparation  of  the  Teacher.— While  wide  and  pro- 
found knowledge  will  find  ample  scope  in  such  work,  let 
no  one  hesitate  because  of  lack  in  that  direction.  Do  not 
cram  in  any  case.  Handle  over  the  material  and  study  it 
in  connection  with  what  you  find  in  books.  Especially 
think  over  the  matters  which  may  not  be  clear,  try  to 
imagine  just  how  things  were  done  or  made,  and  the  sub- 
ject will  grow  in  clearness  and  interest  to  you,  just  as  I 
trust  it  will  to  your  pupils.     If  need  require,  be  a  learner 


296  SYSTEMATIC  SCIENCE  TEACHING. 

with  your  pupils.  No  one  who  has  not  tried  it  knows 
the  delightful  lessons  a  teacher  and  class  can  have  study- 
ing together.  Make  personal  visits  to  all  cuts,  quarries, 
gravel  pits,  ravines,  stone  yards,  mines,  etc.,  there  may  be 
near  you,  so  as  to  gain  in  observation  and  be  ready  to 
lead  field  excursions. 

WinchelFs  book  will  be  suggestive  in  such  "  walks," 
and  if  other  teachers  or  some  geological  friend  can  be 
found  to  keep  you  company,  so  much  the  better.  Bright 
pupils  will  aid  much  in  telling  where  such  things  are, 
and  be  proud  to  show  the  way. 

The  Lessons. 

These  will  consist  in  the  examination  and  discussion 
of  a  series  of  specimens,  the  whole  to  constitute  a  brief 
Story  of  the  Rocks.  Experiments  will  aid  in  under- 
standing, and  field  work  make  the  needed  connection 
with  Nature.  The  child  will  have  a  fund  of  observed 
facts  and  the  experience  of  former  work  to  build  upon. 
The  study  of  the  specimens  will  quicken  his  insight  and 
suggest  questions  for  experiment  and  further  observa- 
tion in  the  field,  these  in  turn  to  further  aid  in  his  com- 
prehension of  this  story. 

I  shall  make  no  attempt  at  division  into  daily  lessons, 
but  only  indicate  the  steps  in  the  work.  Steady  progress 
should  be  kept  up  all  the  time.  Let  full^  neat,  and  well- 
illustrated  notes  be  kept  by  each  pupil  in  uniform  note- 
books. 

Volcanic  and  Dike  Rocks. 

1,  The  first  thing  is  to  give  the  class  a  brief  review  of 
the  nebular  theory  of  the  earth,  leading  up  to  a  concep- 
tion of  its  former  heated  condition,  and  that  the  first 
rocks  cooled  from  a  melted  state.  Why  few  or  none  of 
these  original  ("  Plutonic  ")  rocks  are  known  will  appear 
later.     (Class  keep  full  notes.) 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.     297 

2.  Give  the  class  specimens  of  the  first  eig-ht  rocks, 
and  let  them  write  a  label  to  go  under  each,  numbering 
the  labels  to  correspond  with  the  rocks. 

Place  diagram  No.  1  on  the  board,  and  explain  the  use 
of  different  ways  of  marking  (by  dots,  dashes,  broken 


'^0^^C~''^^ '^^       l"""l  Eruptives. 


^         E21  Granitic. 

\::::::\  Metamorphic. 

Palaeozoic. 
b':':'j  Mesozoic. 
I;g^  Cenozoic. 


Fig.  7.— Section  of  earth's  crust.    (Le  Conte.) 


and  curved  lines,  colors,  etc.)  the  different  strata  on  such 
charts. 

3.  Talk  with  the  class  about  glass  making,  how  sand 
is  hard  to  melt  alone,  but  that  the  addition  of  some  alkali 
(soda,  potash,  or  lime)  or  of  some  metal  (iron  or  lead) 
makes  the  sand  melt  more  easily. 

Show  fragment  of  green  or  blackish  bottle  glass,  that 
the  class  may  see  how  iron  colors  the  glass. 

How  will  iron  affect  the  specific  gravity  of  the  glass  ? 
(Heavier.) 

Let  some  pupils  (after  school)  compare  the  specific 
gravity  of  a  lens  or  imitation  gem  with  some  Bohemian 
or  hard  glass,  and  make  a  written  report.  Which  has 
lead  in  it  ?  Let  others  test  the  fusibility  (on  a  coal  fire 
or  with  blowpipe)  of  various  kinds  of  glass  (black  bottle, 
greenish,  window,  lamp  chimney,  etc.),  and  also  report 
in  writing. 


298  SYSTEMATIC  SCIENCE  TEACHING. 

4.  The  slag  from  iron  furnaces  is  also  a  glass,  which 
results  from  the  fusion  of  the  earthy  impurities  of  the 
ore  with  the  limestone  put  in  for  that  purpose. 

The  class  should  visit  a  blast  furnace  and  bring  home 
samples  of  the  whole  process  for  the  school  and  private 
collections.  If  this  can  not  be,  by  the  aid  of  pictures  and 
samples  go  through  the  steps  very  carefully  with  the 
class,  as  it  will  greatly  aid  in  true  concepts  of  Nature's 
work. 

Why  is  the  slag  so  heavy  ?    (Iron.) 

So  dark  colored  ?    (Iron.) 

Why  is  some  solid,  some  cellular,  and  some  glassy  ? 
(Cooled  slowly ;  pujffed  up  by  the  imprisoned  gases,  or 
cooled  very  quickly.) 

To  show  how  glass  and  slag  resemble  minerals,  let  us 
examine  the  table  on  the  next  page. 

Sand  (SiOa)  behaves  like  an  acid  in  many  ways,  and 
so  is  called  an  "  acidic  "  mineral.  On  the  other  hand,  the 
oxides  (rusts)  of  potassium  (K),  sodium  (Na),  calcium 
(Ca),  magnesium  (Mg),  aluminium  (Al),  or  ferrum  (Fe), 
etc.,  are  called  basic  substances. 

From  the  table  tell  me  the  most  highly  "  acidic  "  sub- 
stance.   (Sand.) 

What  is  its  color  ?    (Light.) 

Its  fusibility  ?    (Very  difficult.) 

What  is  the  most  "  basic  "  glass  ?    (Flint,  or  slag.) 

How  about  the  color,  specific  gravity,  and  melting  of 
slag  ? 

Are  light,  or  dark,  colors  indicative  of  silica  ?    (Light.) 

How  does  lime  (CaO)  seem  to  affect  fusibility? 
(Aids.) 

Are  heavy  minerals  most  apt  to  be  basic,  or  acidic  ? 

5.  By  the  aid  of  pictures  and  written  descriptions  try 
to  give  the  class  some  idea  of  volcanic  phenomena,  refer- 
ring to  the  section  of  the  earth  and  the  specimens  to  illus- 
trate.    (In  referring  to  the  specimens  always  do  so  by 


ROCK 


Y  PHYSICAL  AGENCIES.     299 


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300  SYSTEMATIC  SCIENCE  TEACHING. 

name,  and  let  some  pupil  verify  by  numbers.)  For  such 
descriptions  see  Johonnot's  Geographical  Reader,  The 
Last  Days  of  Pompeii,  and  magazine  articles  on  eruptions 
in  Java,  etc. 

The  matter  thrown  or  poured  out  of  a  volcano  in  a 
melted  state  cools  under  varying  conditions  to  give  us 
these  eight  rocks,  which  are  samples  of  many  kinds. 

Let  the  class  tell  what  they  can  about  these  rocks, 
comparing  them  with  the  artificial  lavas  of  the  glass 
works  and  iron  furnace. 

6.  Question — after  the  pupils  have  told  what  they  can 
— as  follows : 

Which  rocks  cooled  quickest?  (Pumice  and  obsidi- 
an.)   Why? 

Which  slowest  ?  (Granite  and  diorite.)  Why  ? 
(Large  crystals.) 

Which  quickly,  but  under  pressure  ?  (Obsidian.) 
Why  ?     (Compact.) 

Which  quickly  at  the  surface  ?  (Pumice.)  Why  ? 
(Cellular.) 

Judging  by  weight  and  color,  which  is  the  most  acidic 
rock  ?     (Pumice.) 

Others  ?  (Trachyte  and  felsite.)  Which  the  most 
basic  f    (Basalt.) 

Judging  by  the  minerals,  the  most  basic  ?  (Diorite.) 
Why  ?  (Dark,  heavy,  and  of  basic  minerals.)  Name 
any  you  can  distinguish. 

How  about  granite  ?  (Acidic,  as  it  has  much  quartz 
and  white  mica  and  orthoclase.) 

Which  would  melt  the  easiest  ?    (Basalt  and  diorite.) 

Should  the  melted  basalt  flow  over  the  country  in 
lava  floods,  where  would  the  cooling  begin  f  (Next  air 
and  cool  earth.) 

If  it  flowed  between  walls  of  cold  rock  ?  (On  each 
side.) 

Does  rock  expand,  or  contract,  in  cooling  ?    (Contract) 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.     301 


Here  is  a  curious  result  of  this  contraction.  (Show 
pictures  and  specimens  of  columnar  basalt.) 

Who  can  tell  me  which  way  these  columns  always 
run  ?     (From  one  cooling  surface  to  the  other.) 

The  specimen  of  felsite  was  formed  where  ?  (Under 
pressure  in  some  thin  sheet  (dike)  where  it  was  not  very 
long  in  cooling.) 

Which  formed  first,  the 
scattered  crystals  or  the  com- 
pact paste  ?    (Crystals.) 

Any  rock  spotted  with 
scattered  crystals  is  called  a 
porphyry. 

Arrange  a  series  of  speci- 
mens in  the  order  of  cooling. 
(Pumice,  obsidian,  trachyte, 
and  granite ;  or  cellular  lava, 
basalt,  and  diorite.) 

Are  any  of  these  in  layers 
(strata)  ?    (No.) 

Who  can  tell  me  what  must  happen  before  we  can  see 
a  dike  ?  (Erosion,  as  they  are  at  first  covered  up  by  other 
material.) 

7.  Let  the  class  now  draw  and  color  diagram  1. 
This  ends  the  study  of  volcanic  and  dike  rocks. 

New  Ways  of  making  Sharp  Stones. 

Now  proceed  to  consider  how  these  rocks  are  reduced 
to  the  gravel,  sands,  and  soils  of  the  earth,  that  the  pupil 
may  begin  to  understand  how  the  original  rocky  crust 
was  worked  over  to  make  stratified  rocks,  soil,  etc. 

8.  Show  a  rock  cracked  by  frost  or  roots,  and  briefly 
review  Step  XX. 

9.  Show  a  specimen  with  lichens  growing  on  it,  and 
talk  of  how  these  grow  on  the  hardest  and  smoothest 
rocks.     It  is  supposed  these  were  the  first  plants  able  to 


Fig.  8. — Fragment  of  porphyry 
(native). 


302 


SYSTEMATIC  SCIENCE  TEACHING. 


grow  upon  the  bare  rocks  of  the  first  formed  land.  That 
they  could  corrode  the  rock  and  feed  upon  it  is  shown 
by  the  fact  that  plates  of  polished  marble  and  other 
rocks  are  acted  upon  by  roots.  (See  How  Crops  Feed, 
by  Johnson,  p.  326,  and  Physiological  Botany,  by  Good- 
ale,  p.  246,  for  an  account  of  these  experiments.)  Let 
different  members  of  the  class  make  some  polished  sur- 
faces of  marble,  basalt,  limestone,  etc.,  and  try  it. 

10.  Unequal  Expansion  and  Contraction.— Show  the 
class  a  "compound  bar"  (one  made  of  two  metals  riv- 

Copper 

eted  together).     ^^-  -    l-^-I^ 

Iron 


Heat  it  strongly  in  a 


flame  and  observe  the  bending,  thus: 

Why  is  it  curved  ?    (One  metal  expands  more  than 
the  other.) 

Which  most  ?     (Copper.) 

Other  illustrations  are  the  balance  wheels  of  chro- 
nometers and  "  gridiron  "  pendulums  of  fine  clocks. 

Suppose  we   had   cubical  bricks  of  stone  and  copper 
or  iron,  and  should  with  them  build  a  large  and  exact 
cube,  using  alternate  bricks  of  stone  and  metal,  thus: 
Now  let  us  imagine  this  put  into  a 
hot  oven  for  a  time.    What  will  hap- 
pen ?     (Will  expand  as  it  grows  hot.) 

Now  it  has  been  found  that  stone 
expands  much  less  than  metal ;  so,  as 
the  heating  goes  on,  how  about  the 
expansion  of  the  different  kinds  of 
bricks  ?    (Metal  will  expand  most.) 

Let  us  now  take  it  out,  and  when 
cool  what  will  be  the  result  of  this  unequal  expansion  ? 
(Cracks  have  been  opened  by  the  expansion  of  the  metal 
blocks  inside  pushing  out  the  stone  blocks,  and  on  cooling 
the  metal  contracted,  but  could  not  pull  back  the  stone.) 


Fig.  9. 


ROCK  MAKING  BY   PHYSICAL  AGENCIES.     303 

Metal  set  or  melted  into  glass  or  stone  frequently  be- 
comes loose  in  this  way. 

Careful  tests  have  shown  that  not  only  do  metals  and 
stone  differ  as  to  their  rates  of  expansion  and  contrac- 
tion, but  different  kinds  of  stone  do  the  same. 

If  we  could  construct  a  cube  with  blocks  of  pyrite, 
feldspar,  mica,  and  quartz  and  heat  it,  what  would  be  the 
certain  result  ?    {Cracks  would  be  made.) 

Now,  how  are  rocks  usually  constructed  ?  (Of  mingled 
crystals  of  several  different  minerals.  See  granite,  dio- 
rite,  and  rocks  with  pyrite.) 

If  this  mingled  mass  of  differently  expanding  minerals 
be  exposed  to  the  heating  and  cooling  of  day  and  night, 
summer  and  winter,  what  must  little  by  little  happen  ? 
(Cracks  form.) 

Once  the  cracks  are  begun,  what  will  hasten  the 
crumbling  of  the  rocks  ?  (Water  will  get  in  and  freeze ; 
roots  enter  and  grow,  etc.) 

Why  are  glassy  rocks  and  those  made  of  one  mineral 
more  durable  than  the  other  kinds  ?  (Less  of  this  strain- 
ing from  changes  of  temperature.) 

Why  are  pyrite  or  grains  of  magnetite  destructive  to 
a  rock  ?  (Expand  much  more  than  the  other  minerals, 
and  cause  cracks.)  Show  rock  containing  pyrite  or  mag- 
netite and  coarse-grained  granite  and  diorite. 

Show  rocks  scaling  off'  on  the  surface.  Can  any  one 
suggest  a  way  in  which  this  may  have  happened  ?  Re- 
mind, if  need  be,  of  the  effects  of  sudden  changes  of  tem- 
perature through  dashes  of  rain  on  a  hot  day,  sudden  and 
cold  winds,  etc.  (see  Step  XXXI,  Exp.  26). 

A  proof  of  this  is  found  in  the  bowlders  scattered 
over  the  northern  portions  of  the  continents.  When  the 
soil  is  removed  from  those  covered,  and  they  are  exposed 
to  the  sun,  many  soon  begin  to  scale  off. 

11.  Effects  of  Wetting.— Let  members  of  the  class 
weigh  fragments  of  different  rocks  when  dry  ;  soak  twen- 


304  SYSTEMATIC  SCIENCE  TEACHING. 

ty-four  hours  in  water,  and  after  wiping  well  weigh  again 
and  report  results  in  writing.  Place  this  report  on  the  board 
for  the  class  to  put  in  their  notes.  It  will  quickly  be  seen 
that  some  rocks  absorb  much  and  others  very  little  water. 

What  two  results  will  follow  ?  (Those  that  absorb 
water  will  become  softer  and  be  more  acted  upon  by  frost.) 

Two  cubes  of  clay  will  illustrate  the  first  by  finding 
how  many  bricks  can  be  piled  on  before  crushing  occurs 
in  the  case  of  a  dry  cube,  and  also  of  a  moist  one.  Cray- 
on, brick,  shale,  and  sandstone  might  be  tested  in  the 
same  way.  The  action  of  frost  is  illustrated  by  every 
brick  wall,  the  tile  in  the  mouths  of  drains,  plaster  and 
concrete  exposed  to  the  weather,  and  the  poorer  kinds  of 
limestone  and  shale  at  times  used  for  walls,  walks,  etc. 

12.  Rusting  and  Effect  of  Oxygen,  etc.— This  wetting 
is  a  great  aid  to  the  air  in  acting  on  rocks. 

Here  is  a  bottle  of  iron  sulphate.  One  way  of  getting 
this  is  to  pile  pyrite  in  heaps  and  keep  it  wet.  The  oxy- 
gen of  the  air  acts  on  the  pyrite  and  changes  it  to  iron 
sulphate,  which,  being  very  soluble  in  water,  is  washed 
out  and  crystallized  for  sale.  So  actively  does  the  oxy- 
gen act  that  it  is  said  such  piles  frequently  take  fire. 

Pyrite  in  coal  has  also  been  the  cause  of  ships  laden 
with  large  cargoes  of  coal  taking  fire  from  the  action  of 
the  sea  water  on  the  pyrite. 

Not  only  is  this  iron  sulphate  very  soluble  in  water, 
but  when  exposed  to  the  air  it  quickly  swells  (show  bot- 
tle), and  also  turns  to  brown  iron  rust  (see  rusted  pyrite). 

Explain  the  brown  stains  so  frequent  on  walls  and 
stonework.  (Pyrite  changed  to  iron  sulphate ;  the  rain 
washed  this  out,  and  as  it  ran  down  the  stone  the  air 
changed  it  to  brown  limonite.) 

Why  has  coal  frequently  a  rusty  look  ?    (Same.) 

Why  are  ships  laden  with  coal  bad  to  insure  ? 

If  you  were  going  to  build  a  stone  house,  what  min- 
eral would  you  wish  to  avoid  ?     (Pyrite.) 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.     305 

Give  your  reasons.  (It  would  cause  cracks  by  ex- 
panding, wash  out  after  change  to  iron  sulphate,  and 
cause  rust  stains.) 

Yes,  and  there  is  another  way  in  which  it  would  tend 
to  tear  your  house  down. 

I  once  left  a  small  candy  jar  full  of  the  green  crystals 
of  iron  sulphate  for  a  whole  year  with  only  a  loose  cover 
on.  When  I  examined  it  the  green  crystals  had  crumbled 
to  such  a  bulk  of  brownish- white  powder  that  the  cover 
was  lifted  clear  off,  and  much  lay  in  a  pile  about  the  jar. 

Another  example  is  this  bottle  of  air-slacked  lime. 

Who  can  tell  how  lime  is  made  ?  (Limestone  is 
heated  (burned)  till  the  COa  is  driven  off.) 

What  happens  when  this  is  done  is  shown  by  this  de- 
formed brick.  A  piece  of  limestone  was  in  the  clay, 
which,  when  the  brick  was  burned,  became  lime,  and 
swelled  so  as  to  burst  the  brick. 

Have  any  of  you  observed  other  examples  of  lime 
swelling  ?  (When  the  mason  puts  water  on  it  to  make 
mortar  it  grows  hot,  swells,  and  crumbles  to  powder.) 

Yes,  and  T  once  saw  some  barrels  of  it  which  had 
been  stored  too  long  in  a  damp  warehouse.  It  had  taken 
water  from  the  air,  and  not  only  were  the  barrels  heap- 
ing full,  but  almost  every  one  had  hurst  its  hoops. 

Should  water  and  air  cause  pyrite  to  change  to  other 
things  inside  a  rock,  what  would  happen  ?  (Tend  to  pry 
the  crystals  apart.) 

There  are  other  minerals  which  would  behave  in 
much  the  same  way,  but  pyrite  will  do  for  a  sample. 

13.  Solution. — We  have  already  seen  how  some  of  a 
rock  (pyrite)  can  be  washed  out.  There  are  other  ways 
in  which  water  acts.  In  the  study  of  Rounded  Pebbles 
(Step  XV)  we  followed  the  vapor  of  water  as  it  rose  from 
the  sea,  traveled  with  the  wind  over  the  land,  condensed 
on  cool  mountain  tops  or  by  cool  winds  to  rain,  and,  fall- 
ing, made  brooks  to  round  the  sharp  fragments  made  by 
21 


306  SYSTEMATIC  SCIENCE  TEACHING. 

frost,  etc.,  and  wear  the  land  into  hills  and  valleys.  At 
that  time  we  spoke  of  a  part  which,  instead  of  running 
ojf,  sank  in.  Let  us  now  follow  this  portion  and  see 
what  it  does  in  earth  making. 

The  rain  in  falling  through  the  air  dissolves  some  of 
the  COa  and  other  things  it  meets  there.  Soaking  into  the 
decaying  leaves  of  the  forests  and  turf  of  the  fields  it  gathers 
more  COa,  and  becomes  carbonated  water.  Test  some  such 
water  with  lead-acetate  solution  (milky  precipitate). 

Let  us  see  how  this  affects  the  rocks. 

Experiment. — Here  is  an  eight-ounce  bottle  with  a 
rubber  cork  which  fits  it  snugly.  I  will  fill  it  full  of 
water,  cover  the  mouth  with  this  glass  slip,  and  invert  it 
in  this  pan  of  water.  I  use  this  apparatus  to  run  in  COa 
gas  (see  Exp.  4,  Step  XXXI)  till  one  third  of  the  water  is 
displaced.  Next  I  cork  it  under  water,  and  then  shake 
sixty  times.  Eeplacing  the  mouth  below  the  water,  I 
will  loosen  the  cork,  while  you  watch  the  surface  of  the 
water  in  the  bottle.  It  rises.  Why  ?  (Gas  has  been 
partly  absorbed  by  the  water.)  Shake  again  and  repeat. 
See,  nearly  all  the  COa  has  been  taken  up,  and  we  now 
have  a  bottle  of  "  carbonated  "  water.  I  drop  in  a  bit  of 
blue-litmus  paper.  (Turns  red.)  This  shows  the  water 
is  slightly ?     (Acid.) 

Watch  closely  while  I  put  in  this  dropper  full  of 
strong  limewater.  (Milky,  and  then  clears  again.)  Yes, 
the  COa  and  lime  at  first  made  a  little  cloud  of  calcinm 
carbonate,  but  the  acid  water  quickly  dissolved  it.  Re- 
peat this  as  long  as  the  water  will  dissolve  the  milky 
cloud,  shaking,  if  need  be,  to  make  it  do  so.  If  an  esti- 
mate is  now  made  as  to  the  number  of  c.  c.  of  limewater 
that  have  been  added,  the  solvent  power  of  COa  water  on 
lime  will  be  a  surprise  to  all.  Test  a  little  of  this  water 
for  lime  by  ammonium  acetate.  What  other  minerals 
are  much  like  this  calcium  carbonate  in  composition  ? 
(Marble,  limestone,  and  dolomite.) 


ROCK  MAKING  BY   PHYSICAL  AGENCIES.     307 

Kentucky,  Palestine,  and  other  regions  are  underlaid 
by  limestone,  which  has  cracks  (joints),  letting  the  sur- 
face water  down  among  the  rocks.  (See  Geographical 
Reader,  or  other  description  of  the  wonders  of  Mammoth 
Cave,  and  read  to  the  class  or  tell  them.) 

How  do  you  explain  such  caverns  in  limestone  ? 
(Carbonated  water  has  slowly  removed  the  stone.) 

Kentucky  has  always  been  famous  for  its  fine  cattle 
and  horses.  Why  is  the  State  so  good  for  stock  ?  (Luxu- 
riant grass.) 

Had  this  dense  growth  of  grass  anything  to  do  with 
the  caves  ?  (Rain  got  much  COa  from  the  thick  mat  of 
decaying  turf.) 

We  shall  meet  this  dissolved  limestone  in  curious 
ways  after  a  while  (Step  XL VIII). 

COa  water  can  also  dissolve  iron  from  the  soil  (see  Le 
Conte,  pp.  136,  137). 

Did  you  ever  see  rust  stains  on  white  cloth,  or  notice 
grass  or  wood  that  had  been  in  contact  with  rusty  iron  ? 
(The  iron  seemed  to  have  rotted  the  cloth  and  wood.) 

Yes ;  it  was  really  burned.  This  would,  if  continued, 
change  the  red  rust  to  brown  limonite.  Here  is  a  bottle 
of  freshly  boiled  water.  The  COa  has  been  nearly  all 
driven  off  by  the  boiling,  and  I  will  put  in  this  brown 
clay  (or  gravel)  and  cork  it.  John  may  shake  it  while  I 
l)ut  some  of  the  same  clay  (or  gravel)  in  this  bottle  of 
freshly  carbonated  water.  Samuel  may  shake  this  while 
I  show  the  class  a  very  delicate  test  for  iron  in  solution. 
Then  we  will  test  the  water  we  have  been  shaking. 

1.  Water  -I-  HCl  -I-  KCyS  =  nothing  (the  water  is  free 
from  iron). 

2.  Add  to  1  —  a  pinch  of  FeS04  =  blood-red  color. 
This  makes  an  easy  and  sure  test  for  iron. 

Now  filter  the  water  from  our  two  bottles  and  see. 
1.  Boiled  water  +  red  clay  +  HCl  +  KCyS  =  no  trace 
of  iron. 


308  SYSTEMATIC  SCIENCE  TEACHING. 

2.  Carbonated  water  and  red  clay  +  HCl  +  KCyS  = 
red  tinge  (iron  in  solution). 

In  the  short  time  we  shook  it  only  a  trace  of  iron 
could  dissolve,  but  when  such  water  is  slowly  soaking- 
through  gravel  and  sand  beds  all  day  long  year  after 
year  such  "  littles  "  become  like  the  drops  in  the  ocean 
or  sand  grains  on  the  shore — a  great  deal. 

Why  are  some  clays  and  sands  gray  ?  (Iron  washed 
out.) 

Explain  why  the  clay  under  peat  bogs  and  masses  of 
rotting  leaves  in  forests  is  light  colored.  (COa  from 
above  removes  iron.) 

In  what  are  called  "  red  "  clay  or  gravel  lands  the  soil 
by  a  rotten  stump  and  by  the  edges  of  gullies  where  wa- 
ter runs  is  often  gray.     Why  ? 

Carbonated  water  can  dissolve  the  alkalies  of  feldspar. 
Examine  granitelike  bowlders  and  see  if  there  is  any 
evidence  that  some  kinds  of  mineral  are  being  removed 
faster  than  others  (rough  surface,  the  quartz  grains  stand- 
ing up  above  the  feldspar). 

Which  is  seemingly  untouched  by  the  weather  ? 
(Quartz.) 

As  the  alkali  of  the  feldspar  is  removed  there  re- 
mains a  clay  with  the  sand  grains  scattered  through 
it. 

Will  such  a  clay  be  red  ?    (No  iron.) 

If  the  rotten  rock  contains  hornblende  or  augite  ? 
(Brown  clay  from  the  abundant  iron.) 

Mineral  Springs.— As  the  rain  thus  washes  the  alka- 
lies from  the  feldspars,  the  iron  from  the  soil,  and  eats 
the  limestone  into  caves,  it  is  sinking  lower  and  lower 
through  the  crust.  Some,  indeed,  runs  off  in  under- 
ground streams  (Echo  River,  in  Mammoth  Cave),  but 
much  of  it  keeps  on  sinking  till  it  comes  to  some  solid 
layer  (stratum)  of  clay  or  rock  it  can  not  get  through.  It 
is  then  obliged  to  soak  along  in  whichever  way  the  layer 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.    309 

slants  till  it  comes  to  some  bank  or  crack,  where  it  issues 
as  a  mineral  spring. 

What  "  mineral "  this  spring  will  contain  depends  on 
what  it  has  found  to  dissolve  in  the  rocks  and  soils  it  has 
passed  through.  If  through  limestone,  it  will  be  a  "  hard  " 
water  (curdles  soap). 

If  through  red  clays  and  gravels,  it  will  be  an  "iron" 
water,  and  make  everything  around  it  brownish,  like  the 
pyrite  stains  on  stone. 

If  through  rocks  containing^  feldspar,  it  will  be  "soft," 
with  alkali. 

If  through  salt  deposits,  it  will  be  a  "  salt "  spring. 

Have  the  class  draw  diagrams  showing  the  origin  of 
springs  and  artesian  wells.  Also  model  in  clay  or  with 
sheets  of  oilcloth  or  rubber  for  the  lower,  impervious  lay- 
ers, and  sand  or  fine  gravel  for  the  water  to  pass  through. 

14.  These  cause  what  is  termed  weathering: 
Splitting  by  roots  and  frost ; 

Corroding  by  lichens  and  plants ; 

Unequal  expanding  and  contracting ; 

Softening  and  solution  by  water ; 

Changing  by  the  0  and  CO3  of  the  air ; 

Dissolving  by  carbonated  water. 

Some  rocks  we  have  found  very  weak  because  of  their 
mixed  crystals ;  others  weather  much  more  slowly  (or  not 
at  all)  if  of  one  mineral  or  protected  by  a  layer  of  soil. 

How  has  Nature  arranged  to  keep  the  surface  clean, 
so  that  the  weathering  can  go  on  ?    (Winds  and  rain.) 

Yes,  these  keep  up  a  continual  dusting  and  washing, 
leaving  the  rock  in  the  best  possible  condition  for  more 
weathering. 

15.  There  is  one  other  very  interesting  and  remark- 
able way  in  which  sharp  stones,  pebbles,  etc.,  are  made. 
This  is  by 

Glaciers. — We  have  more  than  once  noticed  how  the 
cool  tops  of  mountains  caused  the  moisture  of  winds  to 


310  SYSTEMATIC  SCIENCE  TEACHING. 

fall  on  them  as  snow.  Now,  even  under  the  great  heat 
of  the  tropics  (what  are  they  ?)  some  high  mountains 
keep  this  snow  cap  all  the  time,  while  at  the  polar  re- 
gions much  more  snow  falls  each  year  than  the  short 
summer's  heat  can  melt. 

What  very  terrible  thing  might  have  been  left  un- 
provided for  had  human  wisdom  had  the  planning  of 
this  beautiful  world  ?  (The  snow  would  have  kept  piling 
up  higher  and  higher  on  the  mountains  till  it  fell  over 
on  the  surrounding  country,  and  at  the  poles  till  the 
oceans  were  drained  dry  and  the  earth  began  to  reel 
under  the  shifted  load,  and  death  reigned  supreme.) 

How  this  unmelted  snow  is  to  get  melted  and  return 
to  the  oceans  is  the  interesting  subject  we  will  now  con- 
sider. 

When  a  boy  I  used  often  to  see  where  the  prairie 
chickens  had  been  burrowing  in  the  snow  banks,  or  the 
coveys  of  quail  had  been  huddled  under  some  snow- 
laden  bush. 

What  did  the  birds  want  in  the  snow  ?  (To  keep 
warm.) 

Suppose  I  had  a  fur  coat  hanging  in  a  cold  shed 
where  no  fire  was ;  would  the  coat  be  warm,  or  cold,  to 
a  thermometer  ?    (Cold  as  the  shed.) 

But  if  I  put  it  on  it  would  make  me  feel  warm. 
(Would  keep  the  heat  of  the  body  from  getting  out  and 
being  lost.) 

Why  was  it  that  when  we  used  to  haul  hay  or  straw 
and  stack  it  on  the  frozen  surface,  the  ground  would  soon 
become  thawed  out  under  the  stack  ?  (Kept  heat  of  the 
earth  in,  as  the  coat  kept  that  of  the  body.) 

A  heavy  fall  of  snow  often  comes  on  the  hard-frozen 
ground.  If  it  lies  for  some  time  what  takes  place  under 
it  ?    (Ground  thaws.) 

Doubtless  you  have  seen  the  large,  handsome  St.  Ber- 
nard dogs.    Why  are  they  so  called  ? 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.     311 

What  wonderful  things  are  told  of  them  ? 

Now  these  things  happened  near  or  among  these  very- 
snows  we  have  been  talking  of,  and  so  dangei-ous  and 
difficult  was  it  to  get  over  the  high,  snow-clad  Alps  that 
men  set  to  work  to  make  the  famous  hole  through  the 
hard  rock  called  the  Mont  Cenis  Tunnel.  The  work- 
men here  were  much  troubled  by  the  great  heat  in  the 
mountain. 

Now,  do  these  hints  and  illustrations  help  you  to  see 
what  will  happen  to  the  snow  cap  on  a  mountain  too 
high  for  the  sun  to  melt  it  off  ?  (The  snow  will  melt 
underneath.) 

Good !  I  am  glad  you  thought  of  it,  for  that  is  just 
what  must  happen.  It  does  not,  however,  melt  to  water, 
as  you  suppose. 

When  wet  snow  is  squeezed  hard  what  does  it  turn 
into  ?    (Ice.) 

Yes,  and  as  the  piled-up  snow  must  be  very  heavy, 
what  will  happen  to  the  lower  layers  ?  (Will  be  squeezed 
to  ice.) 

Now,  melting  ice  is  a  curious  substance.  A  machine 
has  been  made  in  which  fragments  of  ice  become  a  solid 
ball  or  cup  or  cube  by  simple  pressure,  the  pieces  freez- 
ing together  as  though  water  had  been  poured  in  the 
mold  and  frozen  (see  Le  Conte,  p.  59). 

If  you  want  to  try  some  experiments,  drop  some  pieces 
of  ice  in  warm  water,  and  when  flat  surfaces  are  brought 
together  you  will  find  they  freeze  into  one. 

Pass  a  thin  copper  wire  over  a  cake  of  ice  supported 
on  two  chairs  and  hang  a  large  stone  to  the  wire.  After 
a  while  the  wire  will  have  passed  clear  through  the  ice, 
which,  however,  is  still  one  block.  How  did  it  happen  ? 
(Wire  conducted  the  heat  into  the  ice  and  so  melted  its 
way  through,  but  the  ice  refroze  as   fast  as  the  wire 

•) 
Heavily  loaded  sleds  (with  iron  shoes)  often  "stick" 


312  SYSTEMATIC  SCIENCE  TEACHING. 

when  they  stand  a  moment.  Why  ?  (The  "  shoes  "  be- 
came warm  through  friction,  and  when  the  sled  stopped 
a  thin  layer  of  water  formed  under  the  shoe  and  froze  it 
to  the  surface  on  which  it  rested.) 

Now,  to  go  back  to  the  snow  on  the  mountains :  The 
heat  from  below  softens  the  snow,  the  great  pressure 
squeezes  it  into  ice,  and  also  forces  it  slowly  out  from 
under  the  snow  into  the  valleys  on  the  sides  of  the  moun- 
tain, where  it  becomes  the  ice  rivers  we  call  glaciers. 
These  are  slowly  (two  or  three  feet  a  day)  forced  to  slide 
down  the  valleys,  gathering  on  their  backs  great  loads  of 
stones  and  earth  from  the  mountain  sides  through  which 
they  jjass.     (Show  pictures.) 

What  will  be  the  effect  on  stones  which  get  between  a 
glacier  and  the  sides  or  bottom  of  the  valley  ?  (Crushed, 
rubbed,  and  scratched.) 

Here  is  one  of  these  "  glaciated  pebbles,"  as  we  call 
them.  See  how  worn  and  scratched  it  is.  What  will  be 
the  effect  on  the  valley  ?    (Also  scratched  and  worn.) 

Yes  ;  look  at  this  piece  of  rock  cut  from  such  a  valley 
bed.  So,  grinding  and  crushing  the  rocks  in  or  under  it, 
and  scratching  and  polishing  the  bottom  and  sides,  the 
glacier  moves  on  till  it  gets  into  the  warm  valleys.  Here 
it ?    (Melts.) 

Yes,  and  drops  the  loads  of  earth  and  rock  it  has 
brought. 

The  rubbing  of  things  together  always  causes ? 

(Heat.) 

Which  will  do  what  to  the  under  surface  of  the  gla- 
cier ?    (Melt  it.) 

This  explains,  in  part,  the  stream  of  water  we  always 
find  issuing  from  the  end  of  a  glacier. 

Is  it  clear,  or  muddy,  water  ?    (Muddy.) 

Why  ?     (From  the  worn  rocks.) 

Name  some  such  rivers.  Could  you  examine  the  end 
of  a  glacier,  what  would  you  see  ?    (Heaps  of  mixed 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.     313 

earth  and  stones,  part  of  the  latter  still  "  sharp  " — never 
having"  got  beneath  the  ice — and  part  rounded  and 
scratched.  The  bed  rock  and  sides  of  the  valley  would 
also  be  scratched  and  polished.) 

If  you  should  find  such  mixed  material  where  no 
glacier  was,  what  would  you  conclude  ?  (That  one  had 
been  there  at  some  time.) 

Look  about  this  place,  where  wells,  cuts,  or  quarries 
have  cut  into  the  earth,  and  see  if  you  find  any  signs  of 
this  land  we  dwell  on  ever  having  been  connected  with 
glaciers. 

So  much  for  the  mountains  in  countries  where  the 
valleys  are  warm.  But  this  will  not  apply  to  lands  in 
polar  regions,  where  the  summers  are  short. 

Name  such  a  country.     (Greenland,  Iceland,  Alaska.) 

As  the  snow  keeps  piling  upon  the  land  the  glaciers 

have  to  keep  pushing  out  till  at  last  they  come  to ? 

(The  sea.) 

On  they  advance  into  deeper  and  deeper  water,  till 

the  end  at  last  floats,  and  huge  pieces  break  off  as ? 

(Icebergs.) 

(See  excellent  illustration  in  Le  Conte,  pp.  43-65.) 

Now  look  at  this  chart  of  ocean  currents  and  tell  me 
what  is  the  end  of  this  ?  (Icebergs  are  carried  by  cur- 
rents into  warmer  waters,  and  there  melt,  dropping  their 
loads  of  stone  and  earth  in  huge  submarine  "banks.") 

The  name  of  both  "  bank  "  and  of  a  very  useful  fish 
which  feeds  on  something  which  likes  to  live  in  the  mud 
and  stones  found  there,  I  saw  marked  on  a  box  in  the 
grocery.    See  if  you  can  find  what  it  is  ?     (Geo.  Codfish.) 

Find  Georges  and  Grand  banks  on  the  map,  and  the 
next  time  you  have  fish  balls  tell  the  family  how  the 
"  banks  '■  came. 

How  have  we  got  our  piled-up  snows  back  to  the 
ocean  ?  What  have  we  found  was  another  way  of  mak- 
ing sand,  gravel,  etc.  ? 


314  SYSTEMATIC  SCIENCE  TEACHING. 


This  Mixed  Material  Sorted. 

16.  As  the  rocks  are  cracked  by  roots  and  frost  and 
the  heat  of  the  sun,  eaten  away  by  roots  and  COa  water, 
and  rubbed,  ground  up,  and  crushed  by  glaciers  and 
moving  water,  the  sand,  clay,  and  pebbles  made  are  also 
sorted  into  beds. 

What  is  it  that  can  do  this  ?    (Moving  water.) 

Yes.  Let  us  think  of  a  brook  or  river.  We  know 
that  the  deeper  it  gets  the  harder  it  must  press  on  and 
against  anything  on  the  bottom.  We  also  know  that  the 
swifter  a  thing  moves  the  more  work  it  can  do. 

When  are  brooks  and  rivers  the  swiftest  and  deepest 
with  us  ?    (In  the  spring.) 

That  is  also  the  time  when  the  ground  is  soft,  and 
loose  from  its  winter's  freezing,  and  as  the  water  rushes 
along  it  tears  away  its  banks  and  gathers  up  much  of  the 
loose  material  made  by  weathering.  The  turbid  mass  of 
muddy  water  rushes  on,  carrying  the  sand  and  mud,  and 
pushing  or  rolling  the  gravel  and  stones. 

Presently  it  comes  to  a  lake  or  ocean.  As  it  runs 
against  this  body  of  stiller  water  the  current  of  the  river 
has  a  check. 

How  will  its  carrying  power  be  affected  ?     (Lessened.) 

Which  part  of  its  load  will  be  first  dropped  ?  (Peb- 
bles and  stones.) 

Then  a  little  farther  on  will  drop  the ?    (Sand.) 

While  from  the  quiet  waters  of  which  it  has  finally 
become  a  part  will  slowly  settle  the ?    (Mud.) 

Confirm  this  by  out-of-door  observations. 

Let  us  represent  the  sorting  in  this  long  box. 

At  this  upper  end  we  will  put ?    (Coarse  gravel.) 

Next  ?    (Fine  gravel.) 

Then  ?    (Coarse  sand.) 

Followed  by ?    (Fine  sand.) 

Last  of  all  ?    (Mud.) 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.     315 

As  the  snows  melt  and  disappear,  and  the  spring  rains 
are  past,  how  will  the  speed  and  quantity  of  water  in  the 
brook  vary  ?    (Become  less.) 

Where  now  will  the  pebbles  be  left  ?     (Higher  up.) 

Beginning  a  second  layer  in  our  long  box,  what  shall 
we  put  on  first  ?    (Fine  gravel.) 

Next  ?    (Coarse  sand,  etc.) 

What  do  we  notice  in  this  new  arrangement  ? 
{Coarser  overlaid  hj  finer  material.) 

As  the  river  becomes  still  lower,  what  will  be  the 
order  ?    (No  gravel ;  only  sand  and  mud.) 

Yes ;  and  perhaps  in  the  very  driest  months  the  river 
will  be  clear  of  even  that,  and  nothing  be  added. 

Next  winter's  high  water  will  repeat  this,  and  so  the 
lake  slowly  but  surely ?     (Fills  up.) 

Which  end  will  fill  first  ?    (Where  the  river  enters.) 

How  high  ?  (Only  as  high  as  the  spring  freshets  can 
raise  the  material.) 

Is  the  mouth  of  the  river  blocked  up  ?  (No,  it  fills  on 
either  side,  but  keeps  one  or  more  mouths  open.) 

Look  on  your  maps  and  find  the  mouths  of  rivers  en- 
tering lakes  or  oceans,  and  see  what  these  fillings  and 
extensions  are  called.     (Deltas.) 

How  are  deltas  made  ?  Why  have  these  often  several 
mouths  of  the  river  running  through  them  ?  What  kind 
of  land  are  they  apt  to  be  ?     (Swampy.) 

Will  it  be  fertile,  or  barren,  land  ?     (Very  fertile.) 

Oceans.— The  sorting  is  also  done  along  all  beaches, 
but  in  a  different  way. 

How  does  the  water  move  ?    (Up  and  back  in  waves.) 

(Have  pictures  of  waves,  etc.,  before  the  class.) 

As  the  wave  advances  toward  the  shore  the  bottom 
strikes  the  shelving  beach  first  and  is  checked,  while  the 
top,  continuing  on  breaks  on  the  shore.  A  great  agita- 
tion is  caused  by  this  among  the  sand  and  gravel  of  the 
beach,  which  we  will  try  to  think  more  about.    First,  the 


316  SYSTEMATIC  SCIENCE  TEACHING. 

bottom  is  plowed  up  and  violently  carried  forward  by  the 
advancing  foot  of  the  wave.  Next,  the  more  rapidly 
moving  crest  makes  a  headlong  plunge  among  the  stones 
and  gravel,  driving  them  against  each  other,  up  the 
beach  and  against  any  clifp  there  may  be.  While  this  is 
taking  place  the  foot  of  the  wave  will  have  begun  to  run 
back  (as  undertow),  and  will  be  followed  by  the  retreat- 
ing water  of  the  crest.  What  severe  rubbing  and  knock- 
ing together  this  means  for  the  stones  and  sand  of  the 
beach  we  have  before  considered,  and  will  be  especially 
realized  by  those  who  have  been  tumbled  about  in  heavy 
surf  while  bathing.  The  sorting  will  also  be  readily  un- 
derstood, for  the  retreat  of  the  wave  carries  the  pebbles 
with  a  rattling  noise  down  the  beach,  to  drop  them  as  its 
force  becomes  lost,  while  the  fine  mud  may  remain  sus- 
pended for  some  little  distance  from  the  shore,  there  to 
be  caught  in  the  currents  of  the  ocean  and  carried  many 
miles  before  settling.  The  tides  also  help,  but  we  must 
not  speak  of  them  here  (see  Step  XLII,  §  14). 

Solutions  deposited— Chemically  Formed  Rocks. 

17.  Now  that  the  fragments — gravel,  sand,  and  clay — 
have  been  laid  to  rest  on  the  bottoms  of  lakes  and  oceans, 
let  us  consider  those  portions  of  the  rocks  which  were 
dissolved. 

What  substances  were  these  ?  (§  13,  lime,  iron,  al- 
kali, and  salt.) 

Lime  Deposits. — l.  Look  in  the  teakettle  at  home  and 
bring  some  of  the  "scale  "  you  will  probably  find. 

Where  has  it  come  from  ?     (The  water.) 

Yes.    What  enables  the  water  to  dissolve  limestone  ? 

(COa.) 

Now  COa  can  not  stay  in  the  boiling  water  of  a  kettle, 
and  when  it  escapes  the  lime  is  no  longer  soluble,  and 
settles  on  the  sides. 

Here  are  some  of  the  curious  iciclelike  Stalactites  you 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.     317 

will  remember  as  hanging  from  the  roof  of  Mammoth 
and  other  caves. 

How  did  they  form  ?  (COa  water  dissolved  the  lime- 
stone above,  and  as  it  trickled  down  and  dripped  from 
the  roof  some  of  the  lime  was  deposited  and  finally  grew 
into  these.) 

But  all  the  lime  is  not  deposited  by  the  water  before 
it  drips  from  the  stalactite.  See  this  Stalagmite,  as  it  is 
called.  This  is  formed  below,  where  the  water  drips  or 
flows  off  in  thin  sheets. 

How  do  you  account  for  the  columns  of  such  mate- 
rial in  caves  ?  (Stalactite  and  stalagmite  have  grown  till 
they  met  and  united.) 

An  interesting  example  of  the  rapid  growth  of  such 
deposits  was  found  in  the  beer  cellars  of  a  brewery 
burned  during  the  Chicago  fire,  in  1871.  Eight  years 
afterward  stalactites  twenty  inches  long  and  stalagmite 
lumps  one  inch  thick  and  four  inches  in  diameter  had 
formed  from  the  lime  in  the  stone  of  which  the  brewery 
was  built,  aided  by  a  forest  of  rank  weeds  which  had 
sprung  up  on  the  rubbish.  In  the  beautiful  "  Mexican 
onyx  "  is  seen  the  results  of  some  iron  being  in  the  wa- 
ter, causing  bands  of  brown  or  black. 

The  story  is  told  of  a  coal  mine  in  which  a  deposit  of 
white  stalagmite  was  forming.  During  the  week  the 
coal  dust  settled  on  the  white  stone  and  made  it  black, 
but  when  Sunday  was  observed  a  pure  white  layer  re- 
corded the  fact  in  stone.  Sometimes  the  leaves  and  moss 
about  such  a  spring  are  "  petrified  "  into  a  stony  model  of 
the  substance. 

At  times  this  limy  water  soaks  among  shells,  pebbles, 
or  sand. 

What  will  it  do  to  them  ?    (Cement  together.) 

Show  coquina  from  St.  Augustine,  and  test  plaster 
and  conglomerates  for  the  nature  of  the  cement  by  pow- 
dering some  of    the  cementing  material   and   shaking 


318  SYSTEMATIC  SCIENCE  TEACHING. 

with  weak  HCl  acid,  then  to  the  clear  solution  apply  the 
lime  and  iron  tests.  (See  Solution  13.)  Eifervescence 
will  occur  if  it  is  a  lime  cement.  Having  deposited  some 
of  its  limy  matter  as  stalactites,  stalagmites,  and  cement- 
ing material,  the  water  passes  on  to  the  oceans.  In  the 
early  history  of  the  earth  there  must  have  been  a  great 
deal  of  lime  in  the  sea  water  and  much  COa  in  the  air. 
What  would  happen  from  its  waves  mixing  with  the  air 
heavily  laden  with  COa  can  be  seen  by  filling  an  eight- 
ounce  bottle  with  limewater  and  running  in  COa  gas 
till  half  of  the  water  has  been  displaced.  Cork  well,  and 
shake.  A  white  precipitate  of  calcium  carbonate  will 
form  and  settle  to  the  bottom.  Let  the  class  expose  sau- 
cers of  limewater  for  a  night,  and  a  brittle  skin  of  the 
same  mineral  will  form  on  the  surface  from  the  COa  in 
the  air  uniting  with  the  lime  of  the  water.  The  same 
thing  is  well  seen  where  masons  have  left  water  standing 
in  a  mortar  bed. 

In  the  ocean  this  white  precipitate  would  slowly  set- 
tle to  the  bottom  as  it  formed,  and  the  white  mud  would 
become  limestone  in  time.  Should  another  substance 
called  magnesium  carbonate  form  at  the  same  time  and 
settle  with  the  calcium  carbonate,  another  kind  of  rock 
would  form  called  dolomite. 

If  this  white  mud  should  form  in  shallow  water  the 
gentle  moving  by  the  waves  often  rolls  it  into  little  egg- 
like grains,  which,  cemented  by  the  same  substance, 
forms ?    (Oolite.) 

More  recently — since  life  came  on  the  earth — the  lime 
has  been  removed  from  seas  and  lakes  in  a  remarkable 
way,  which  we  shall  consider  under  Animals. 

Iron  Deposits. — When  iron  is  dissolved  by  carbonated 
water  it  takes  the  form  of  sideiite  (carbonate  of  iron) ; 
and  if  this  water  ran  into  peat  bogs,  or  any  place  where 
there  was  much  decaying  vegetable  matter,  it  would  de- 
posit as  siderite  or  mix  with  the  clay,  becoming  clay 


ROCK  MAKING   BY  PHYSICAL  AGENCIES.    319 

ironstone  when  in  quantity.  Should  this  solution  of 
iron  carbonate  come  to  the  open  air,  the  COa  would  es- 
cape, and  stalactites  and  stalagmites  of  brown  limonite 
might  form,  as  happened  with  the  lime ;  also  leaves,  etc., 
about  such  water  would  be  coated  with  the  brown  rust, 
and  layers  of  pebbles  be  cemented,  as  in  the  specimen  of 
bog  iron.  In  this  way  the  grains  of  iron  scattered 
through  the  sands,  clays,  and  gravel  from  the  weathered 
rocks  would  little  by  little  be  gathered  into  the  immense 
beds  of  iron  ore  we  find  to-day. 

What  must  the  water  hold  in  order  to  dissolve  the 
iron?    (CO2.) 

Where  could  the  COa  come  from  ?  (Decay  of  plants, 
animals,  and  the  air.) 

What  would  be  the  original  color  of  the  sands  and 
clays  containing  iron  ?     (Brownish  red.) 

How  would  the  removal  of  the  iron  change  this  col- 
or ?    (To  grays  and  whites.) 

Might  some  siderite  be  left  in  light-colored  clay  or 
sandstone  ?     (Yes  ;  it  is  a  light-colored  mineral  itself.) 

Gypsum  and  Salt. — As  the  continents  rose  above  the 
sea,  portions  of  the  salt  water  would  be  separated,  as  now 
seen,  in  what  seas  ?    (Caspian,  Dead,  and  Aral.) 

Look  on  the  map  and  see  what  arms  of  the  ocean 
have  narrow  openings  into  the  larger  bodies  of  water. 
(Red,  Black,  Mediterranean,  Baltic,  etc.) 

If  the  mouths  of  the  Baltic  and  Red  Seas  were  closed, 
which  of  them  would  gradually  fill  up,  and,  overflowing 
at  some  point,  be  washed  free  from  salt  and  become  a 
fresh- water  lake  ?     (Baltic.) 

Why  ?  (Because  of  the  slow  evaporation  where  it 
lies,  and  because  so  many  large  rivers  run  into  it.) 

What  would  happen  to  the  Red  Sea  ?  (So  little  water 
fl.ows  in  that  it  would  slowly  dry  up.) 

What  would  happen  to  the  mineral  in  the  water  ? 
(Would  be  left  in  layers  on  the  bottom.) 


320  SYSTEMATIC  SCIENCE   TEACHING. 

To  take  two  examples :  salt  is  very  easily  soluble  in 
water,  while  gypsum  takes  a  great  deal  of  water  to  dis- 
solve it. 

Which  will  deposit  first  in  the  drying  up  of  a  lake  ? 
(The  least  soluble — gypsum.) 

On  top  will  rest  layers  of ?     (Salt.) 

Now,  in  Nature,  salt  mines  are  almost  always  under- 
laid by  beds  of  gypsum.  How  did  the  two  become  so 
placed  ? 

Fragmental  Rocks. 

18.  The  beds  of  gravel,  sand,  and  clay  at  the  bottom  of 
seas,  lakes,  and  rivers  are  under  heavy  pressure.  This  is 
shown  by  corked  bottles  and  apparatus  lowered  into  deep 
water  being  crushed ;  and  wood  sunk  to  great  depth  be- 
comes so  full  of  water  as  not  to  rise  again  (ships). 

Deep-water  fish  show  the  pressure  they  have  lived 
under  by  swelling  up  (red  snapper),  the  stomach  protrud- 
ing from  the  mouth  in  many  cases. 

Divers  for  sponges  and  coral  often  have  their  ear- 
drums burst,  and  come  up  bleeding  from  nose  and 
ears. 

Now  this  pressure,  aided  by  the  cementing  lime  and 

iron  we  have    spoken    of,   makes  of  gravel  beds ? 

(Conglomerate.) 

If  there  are  sharp  fragments  in  place  of  rounded 
pebbles ?    (Breccia.) 

Beds  of  sand  become ?    (Sandstone.) 

Brown  because  of ?     (Iron.) 

Gray  ?    (Because  the  iron  has  been  washed  out.) 

Mud  and  clay  become ?    (Shale.) 

Brownish  if  it  contains ?     (Limonite.) 

Gray  when ?    (The  iron  is  gone,  or  changed  to 

carbonate.) 

Black,  as  in  the  "  slate "   found   in  hard  coal ? 

(When  it  has  carbon  in  it.) 


ROCK  MAKING  BY  PHYSICAL  AGENCIES.    321 

Such  slate,  as  seen  in  the  ashes  after  burning,  is  of 
what  colors  ?    (White  or  red.)     Why  ? 

The  leaves  of  plants,  shells,  and  parts  of  animals  are 
often  beautifully  preserved  in  such  shale,  and  are  called 
fossils. 

Are  these  rocks  in  strata  (layers)  ?    (Yes.) 

Review  had  better  be  delayed  till  the  beginning  of 
Step  XL VIII.  If  the  work  has  been  carefully  done  none 
is  needed  now. 

Material  put  away.— See  Minerals,  Step  XXXVII. 

Earth  Making  is  really  the  first  half  of  Eocks  (the  next 
step  in  the  mineral  series),  and  the  completion  of  the 
study  of  fragmental  and  chemically  formed  rocks  seemed 
a  good  place  to  stop.  As  to  the  interest  and  profit  such 
lessons  are  to  a  class,  one  trial  in  the  way  indicated — 
with  specimens  to  illustrate  all  that  is  said  or  done — will 
be  enough  to  answer  the  question  beyond  dispute.  I 
doubt  if  for  general  mind  building  any  better  material 
can  be  found  than  rocks. 

Next  step,  LXVIII— Rocks. 


STEP  XLV.— FAMILIES  OF  SPRING  PLANTS. 

Object. — By  comparative  study  of  several  members  of 
each,  to  learn  the  characteristics  of  important  families  of 
plants.  Incidentally  to  continue  the  work  begun  in  Step 
XLI.  Accurate  observation  and  concise  description  are 
vital  factors  in  this  work,  and  are  to  be  persistently 
cultivated. 

Time. — About  twenty-five  lessons  of  thirty  minutes 
each  in  the  spring".  Take  up  the  work  whenever  mate- 
rial can  be  had,  alternating  with  other  work  should  the 
supply  fail.  Specimens  should  be  fresh,  although  it  is 
well  to  have  mounted  material  (hereafter  described)  on 
hand  in  case  of  an  emergency. 

The  flowers  of  spring  are  more  simple  and  easily  com- 
pared than  those  of  autumn,  and  hence  best  to  begin 
with.  The  following  list  of  families  and  their  most 
available  representatives  will  indicate  the  general  plan, 
which  has  proved  successful,  and  serve  as  a  model  on 
which  adaptations  can  be  made  for  other  localities. 

The  order  in  which  these  are  studied  is  of  little  con- 
sequence except  in  the  case  of  families  which  are  much 
alike.  These  should  be  studied  consecutively,  that  the 
differences  may  be  more  readily  detected.  Such  are 
grouped  by  brackets. 

Suggested  families  for  the  step,  and  their  most  evident 
general  characteristics:  * 

*  They  are  heris  with  net-veined  leaves,  unless  otherwise 
stated.    Exceptions  are  ignored  at  t^is  stage  of  the  work. 
822 


FAMILIES  OF  SPRING  PLANTS.  323 

1.  Goniferae  (pine,  spruce,  hemlock,  larch,  arbor  vitae, 
etc.)- — Trees  or  shrubs  with  needle-shaped  leaves,  resin- 
ous sap,  and  naked  seeds  in  cones. 

2.  Willows  (willow,  poplar,  cottonwood,  aspen,  etc.). — 
Trees   or    shrubs  with    dioecious    catkins    and    cottony 


3.  Arums  (call a,  Jack-in- the-pulpit,  skunk  cabbage). — 
Monoecious  flowers  on  a  spadix  surrounded  by  a  spathe. 

4.  Horsetails.  —  Plants  with  harsh,  jointed,  leafless 
stems  and  terminal  spike. 

5.  Ranunculacese  (buttercups,  anemone,  hepatica,  col- 
umbine, etc.). — Parts  of  the  flower  all  distinct  and  fall- 
ing to  pieces. 

[6.  LiliacesB  (tulip,  hyacinth,  onion,  lily  of  the  valley, 
etc.).  —  Leaves  parallel- veined.  Perianth  and  stamens 
regular  and  of  same  number.  Style  of  superior  ovary 
undivided. 

[7.  AmaryllidaceaB  (yellow  star  grass,  narcissus,  snow- 
drop).— Same  as  the  lilies  (6),  except  that  the  ovary  is 
inferior. 

[8.  Iridacea  (iris,  crocus,  blue  star  grass,  gladiolus). — 
Smooth,  parallel-veined  leaves,  stamens  only  three,  open- 
ing away  from  inferior  ovary.] 

9.  Orchids  (lady's  slipper,  fringed  and  round-leaved 
orchis,  arethusa,  etc.). — Leaves  parallel-veined.  Very 
irregular  flowers,  the  one  or  two  stamens  cohering  to  the 
pistil. 

10.  Mustards  (stock,  candytuft,  cress,  horse-radish, 
etc.). — Pungent  taste,  the  four  petals  regular,  and  six 
stamens  of  two  lengths. 

11.  Rose  fia.lllily  (apple,  peach,  blackberry,  Geum). — 
Alternate,  stipulate  leaves.  The  regular  corolla,  and 
many  stamens  on  the  calyx. 

12.  Pink  family  (soap wort,  chickweed,  sweet  William, 
etc.). — Simple,  opposite  leaves  from  swollen  joints.  Seeds 
on  free  central  column  of  ovary. 


324  SYSTEMATIC  SCIENCE  TEACHING. 

13.  Pea  family  (vetch,  lupine,  bean,  wistaria,  locust). 
— Compound  leaves,  stipules.  Ten  stamens,  the  fruit  a 
one-celled  pod. 

14.  Umbelliferse  (carrot,  parsnip,  water  hemlock,  etc.). 
— Compound  leaves,  the  bases  sheathing  the  fluted,  hol- 
low stem.     Flowers  in  umbels. 

Preparation  of  the  Teacher.— This  step  and  XL VI  are 
so  related  that  a  study  should  be  made  of  them  together. 

There  is  no  better  preparation  than  to  illustrate  the 
families  on  cards,  which  will  also  be  available  for  class 
work  when  fresh  specimens  can  not  be  had. 

The  Coniferae  is  especially  good  to  begin  with,  as  so 
many  members  of  the  family  are  available  in  parks,  etc., 
at  any  season  of  the  year,  are  so  characteristic,  and  keep 
so  well.  Gather  a  bit  of  the  spray  and  the  cones  of  as 
many  evergreens  as  possible.  Take  a  good  work  on  bot- 
any (or  Newhall's  Trees  of  North  America),  and,  turning 
to  the  family,  compare  your  specimens  with  the  text  and 
with  Step  XII.  Having  learned  each  tree  and  its  charac- 
teristics, press  small  specimens  of  all  the  sprays  (except 
the  hemlocks,  firs,  and  spruces,  which  will  drop  to  pieces 
when  dry),  a  couple  of  the  scales  from  each  kind  of  cone 
with  the  seeds,  if  they  can  be  found. 

Procure  a  couple  of  nurseryman's  illustrated  cata- 
logues and  a  number  of  stiff  cards  6  x  10  inches.  On  these 
paste  the  cuts  of  such  pines  as  your  catalogue  supplies, 
and  beside  each  picture  glue  strongly  a  sprig  of  its  needles 
and  two  scales,  one  with  the  thickened  tip  up,  and  the 
other  reversed  to  show  the  two  seeds  at  the  base.  This 
card  (or  cards)  will  illustrate  the  true  pines  (needles  in 
bundles  of  two  to  five,  and  scales  of  cones  thickened  at 
the  tips). 

On  another  card  place  the  hemlock  and  spruce  (draw- 
ing a  bit  of  the  spray  or  gumming  on  a  few  of  the  scat- 
tered needles)  with  the  #/iin-tipped  scales  of  the  pendant 
cones. 


FAMILIES  OF  SPRING  PLANTS.  325 

On  another,  those  with  erect  cones  (fir  and  larch). 

On  another,  those  with  scale-leaved  sprays,  their  cor- 
responding cone  (or  berry)  entire  (as  in  arbor  vitse,  white 
cedar,  and  red  cedar). 

Compare  in  this  connection  the  corresponding  woods 
of  Step  XIII. 

By  the  time  this  is  done  some  very  substantial  knowl- 
edge of  and  interest  in  an  important  group  of  plants 
will  have  resulted,  and  is  now  available  for  teaching 
others. 

By  methodical  work  in  some  room  where  plenty  of 
table  space  can  be  had  it  is  no  severe  task  to  prepare  ten 
or  twenty  cards  of  each  sort,  and  then  you  are  ready  for 
class  work,  if  fresh  material  can  not  be  had. 

These  cards  will  illustrate  much  of  a  concise  botanical 
description — e.  g.,  Coniferae  :  trees  or  shrubs ;  soft  wood  ; 
resinous  sap ;  awl-  or  needle-shaped  entire  leaves ;  the 
fruit  a  cone  (or  berry),  with  two  or  more  naked  ovules 
(or  seeds)  at  the  base  of  each  scale. 

Proceed  in  like  manner  to  illustrate  the  other  twenty- 
nine  families  given  in  the  two  steps  (XLV,  XL VI),  or 
such  substitutes  as  circumstances  may  direct,  except  that 
it  will  not  be  best  to  subdivide  a  family  as  above  sug- 
gested for  the  Coniferae. 

Gather  t3rpical  material  for  this  wherever  and  when- 
ever it  can  be  had,  label,  press,  and  put  away  till  all  of 
one  or  more  families  is  ready,  and  then  make  one  piece 
of  work  of  the  mounting.  Do  not  label  the  cards  in  any 
way. 

Such  work  of  preparation  may  well  be  the  avocation 
of  the  year  preceding  the  beginning  of  instruction,  and 
will  place  the  teacher  in  a  position  to  do  effective  teach- 
ing with  ease  and  certainty  of  happy  results. 

Plant  seeds,  etc.,  by  the  aid  of  the  class,  to  furnish  ma- 
terial for  the  work  of  the  fall,  which  will  continue  this 
(see  Step  XLVI). 


326  SYSTEMATIC  SCIENCE  TEACHING. 

The  Lessons. 

Do  not  begin  till  a  survey  of  the  available  material 
promises  a  regular  supply,  so  that  the  "  line  upon  line " 
of  practice  can  be  sustained  for  a  number  of  families. 
As  a  model  and  to  unify  the  work  of  the  class,  place  the 
following  order  of  record  on  the  blackboard  and  direct 
the  class  to  follow  it  in  their  study  : 

Order  of  recording  Observations  on  Each  Plant. 

Life— Annual,  biennial,  shrub,  tree,  etc. 
Root — Multiple,  tap,  etc. 

Stem — Endogen,  exogen,  branched,  wood,  sap,  etc. 
Leaf— Position :  alternate  or  opposite.    Vernation,  etc. 
Parts :  stipules,  petiole,  blade,  venation,  simple 
or  compound,  etc. 
Bracts- Position  :  foliaceous  or  floral,  etc. 
Flower — Kind :  perfect,  complete,  regular,  symmetri- 
cal, monoecious,  etc. 
Position:  terminal,  axillary,  raceme,  umbel, 

etc. 
Calyx :  adhesion  or  cohesion,  character,  etc. 
Corolla:  same. 

Stamens  :  same  ;  anthers,  color  of  pollen,  etc. 
Pistils :  same  ;  simple  or  compound,  placenta, 
superior,  etc. 
Fruit— Kind,  structure,  etc. 

Seed — Number,  albuminous  or  exalbuminous,  etc. 
The  record  must  be  kept  in  an  orderly  and  concise 
manner,  using  diagrams  to  save  space  and  add  clearness. 
The  notebooks  should  be  wide  (eight  inches  or  so). 
Having  headed  a  page  with  the  name  of  a  family,  divide 
the  space  into  as  many  perpendicular  columns  as  there 
are  representatives  of  the  family  to  be  studied.  These 
parallel  columns  will  aid  in  seeking  those  resemblances 
which  characterize  the  family. 


FAMILIES  OF  SPRING  PLANTS.  327 

1.  When  these  details  have  been  explained,  bring  as 
complete  specimens  (root,  leaf,  flower,  and  fruit)  as  pos- 
sible of  two  or  more  members  of  the  family.  Give  a 
named  set  to  each  pupil,  who  will  then  proceed  to  head 
the  columns  with  the  names  of  the  plants  and  in  the 
order  g-iven  on  the  board,  to  record  his  observations  un- 
der the  name,  using  any  aids  in  the  way  of  books,  etc., 
he  may  be  able  to  get.  As  this  work  is  classification, 
obvious  differences  should  be  omitted  from  the  record, 
and  only  likenesses  noted.  It  will  be  best  to  make  the 
study  comparative,  recording  the  character  of  the  roots 
of  one  after  another  till  all  roots  have  been  examined, 
then  taking  all  the  stems,  etc. 

2.  When  all  have  completed  their  notes,  have  one 
after  another  read  his  record  of  some  one  point  to  the 
class  for  comparison  and  the  correction  of  mistaken  con- 
clusions. 

3.  Let  each  one  carefully  consider  his  record  and 
decide  on  the  briefest  yet  complete  characterization  of 
all  the  given  plants  (the  family),  write  it  at  the  bottom 
of  the  page,  and  hand  his  book  to  the  teacher  for  inspec- 
tion as  to  neatness,  conciseness,  and  accuracy. 

Would  lay  great  stress  on  these  three  points,  as  much 
of  the  educational  value  of  this  work  lies  in  the  training 
along  such  lines.  Slovenly  work  should  be  rewritten. 
Conciseness  can  only  be  acquired  by  practice,  hence  com- 
mend any  advance  discoverable. 

Accuracy  will  be  the  result  of  a  careful  study  of  the 
material,  recorded  through  a  wide  vocabulary  of  under- 
stood terms.  These  must  be  acquired  if  not  already  pos- 
sessed, and  the  teacher's  criticism  should  guide  in  that 
direction. 

Give  especial  heed  to  the  final  characterization  of  the 
family,  and  while  the  pupil  as  yet  knows  nothing  of  the 
other  twenty-nine  groups  in  this  and  the  related  step,  and 
hence  can  not  yet  say  what  are  the  specific  points  by 


328  SYSTEMATIC  SCIENCE  TEACHING. 

which  to  distinguish  this  from  all  other  families  he  will 
study,  yet  the  teacher  should  see  that  all  such  points  are 
among  those  recorded  by  each. 

Do  not  mark  or  even  tell  the  pupil  what  these  specific 
points  are,  as  that  will  be  his  discovery  when  later  on  he 
has  widened  his  outlook  by  the  study  of  more  groups. 

4.  Return  the  notebooks  and  have  the  class  read  their 
characterizations  aloud  for  mutual  help  and  criticism. 

5.  Give  another  group  and  proceed  as  above.  If  the 
introduction  has  been  carefully  made,  each  will  begin  to 
know  just  what  to  do  and  to  do  it  rapidly  and  correctly. 
After  a  few  times  the  reading  aloud  (2)  for  comparison 
may  be  omitted,  and  each  pupil  work  individually. 

This  individual  and  unaided  work  must  be  constantly 
encouraged. 

Do  not  forbid,  but  rather  try  in  every  way  to  create,  a 
sentiment  which  will  scorn  to  give  or  take  aid,  and  a 
pride  in  independent  eflPort  and  results. 

A  clear  statement  of  the  loss  from  being  helped  and 
the  unkindness  of  helping  has  usually  sufficed  for  the 
majority  of  a  class.  The  minority  must  be  individually 
labored  with. 

To  keep  the  class  reasonably  together  and  yet  encour- 
age prompt  and  accurate  work,  it  will  be  needful  to  pro- 
vide (and  give  distinct  credit  for)  advance  work,  to  utilize 
the  energies  of  the  bright  and  industrious. 

Post  a  list  of  ADVANCE  WORK  open  to  pupils  who  have 
completed  satisfactorily  all  the  groups  supplied,  and  let 
each  choose  what  he  desires  to  investigate. 

The  following  are  some  suggestions : 

1.  Bring  in  new  plants  of  groups  studied. 

2.  Bring  in  families  of  your  own  discovering. 

3.  Illustrate  the  groups  studied  on  cards. 

4.  Begin  an  herbarium  of  one  or  more  families,  neatly 
pressed,  mounted,  and  named  by  some  key. 

5.  With  the  microscope  investigate  the  minute  struc- 


FAMILIES  OF  SPRING  PLANTS.  329 

ture  of  the  seed,  shape  of  pollen,  distribution  of  stomata, 
or  other  peculiarities  of  groups  studied. 

6.  Learn  the  properties,  distributions,  etc.,  of  some 
group. 

7.  Subdivide  families  into  genera. 

8.  Study  the  exceptions  to  the  characterizations  made. 

9.  Continue  and  expand  some  of  the  "  relationships  " 
of  Step  XXVIII. 

As  group  after  group  is  studied  and  its  characteristic 
features  are  sought,  constant  reference  must  be  made  to 
groups  previously  studied,  that  each  description  remains 
clearly  distinctive.  This  will  often  involve  the  striking 
out  of  points  which  at  first  appeared  characteristic,  or  the 
adding  of  features  which  before  seemed  unimportant. 

The  ability  of  the  pupil  to  do  this  without  aid  will  be 
the  measure  of  his  profit  from  the  lessons. 

Continue  the  free  criticism  of  (4)  at  times  by  letting 
volunteers  place  their  characterizations  on  the  board  for 
the  class  to  revise. 

Review  in  various  ways : 

Class  and  teacher  bring  in  new  specimens  of  groups 
studied,  for  the  class  to  locate. 

Teacher  characterize  a  group,  and  class  write  the 
name. 

Pupils  characterize  and  teacher  name,  etc. 

The  results  of  this  work,  done  in  the  independent 
spirit  I  have  tried  to  indicate,  will  amply  repay  the  labor 
of  the  teacher,  and  will  compare  favorably  with  the  sub- 
stantial results  obtained  along  any  other  line  of  true  edu- 
cation. 

The  next  step  will  continue  the  work  of  this  on  the 
flowers  of  autumn— Step  XL VI. 


STEP  XLVL— FAMILIES  OF  AUTUMN  PLANTS. 

Object.— To  continue  the  work  of  the  last  step  by  a 
study  of  the  more  difficult  flowers  of  autumn,  and  further 
advance  the  training  outlined  in  XLI. 

Time. — About  twenty-five  lessons  in  the  autumn,  be- 
fore severe  frosts  kill  the  flowers  and  fruits. 

Material  should  be  fresh.    See  last  step  for  suggestions. 

Suggested  families  for  the  step  and  their  most  evident 
general  characteristics  (exceptions  ignored)  : 

1.  Gourd  (melon,  squash,  pumpkin,  wild  cucumber). — 
Fleshy  herbs  with  tendrils,  flowers  monoecious,  ovary 
inferior. 

2.  Solanums  (tomatoes,  potatoes,  petunia,  tobacco,  etc.). 
— Herbs,  the  regular  flowers  plaited  in  bud,  five  sta- 
mens, and  rank,  watery  juice. 

3.  Mallows  (abutilon,  sida,  hibiscus,  cotton,  etc.). — 
Regular  flowers,  the  many  stamens  cohering  in  a  tube. 

4.  Bindweeds  (morning-glory,  sweet  potatoes,  etc.). — 
Twining  or  trailing  herbs,  corolla  twisted  in  bud,  and 
seeds  albuminous. 

5.  CompositSB  (aster,  golden-rod,  sunflower,  dahlia, 
etc.). — Many,  regular  flowers  in  an  involucrate  head. 
The  inferior  ovary  one-seeded. 

6.  Mints  (salvia,  catnip,  etc.). — Square  stems,  oppo- 
site, pungent  leaves,  irregular  flowers,  ovary  forming 
four  nutlets  in  fruit. 

7.  Figworts  (mullein,  snapdragon,  gerardia,  "butter 
and  eggs,"  etc.).— Resembles  6,  but  not  pungent,  and 
fruit  a  two-celled,  many-seeded  pod. 

330 


FAMILIES  OP  AUTUMN  PLANTS.  331 

8.  Borage  (heliotrope,  puccoon,  stick -seed,  etc.). — 
Fruit  as  in  6,  but  stem  round,  leaves  alternate ;  regular 
flowers  in  scorpioid  racemes,  etc. 

9.  Euphorbias  (any  of  the  spurges). — Milky  sap,  the 
monoecious  flowers  surrounded  by  an  involucre  which  is 
often  petal  oid. 

10.  Oak  (chestnut,  beech,  hazel,  hornbeam,  etc.). — 
Trees  or  shrubs,  the  leaves  simple,  and  fruit  a  one-celled 
nut  in  a  cup  or  burr. 

11.  Hickory  (pecan,  pignut,  black  walnut,  butternut, 
etc.). — Trees,  pinnately  compound  leaves,  fruit  drupelike 
and  embryo  lobed. 

12.  Sedges  (any).  —  Grasslike,  but  the  leaves  with 
closed  sheaths  and  solid,  triangular  stems. 

13.  Grasses  (wheat,  oats,  corn,  timothy,  bamboo,  etc.). — 
Like  12,  but  the  leaves  with  split  sheaths  on  the  round, 
hollow  stem. 

14.  Ferns  (any).  —  Fronds  leaflike,  unrolling  at  the 
tip  in  growth,  spores  in  dots  or  lines  on  the  back. 

15.  Mosses  (any). — Small,  "  flowerless  "  plants,  stem 
and  leaves  distinct,  and  spores  in  a  spore  case. 

16.  Lichens  (any).  —  Incrusting  plants  with  no  dis- 
tinction of  stem  and  leaf,  and  no  spore  case. 

Preparation  of  the  teacher  as  in  Step  XLV. 

The  lessons  should  begin  as  in  the  last  step,  but  the 
pupils  will  need  less  oversight,  and  can  more  quickly  be 
left  to  original  methods.  If,  as  suggested  in  the  last  step, 
seeds  and  slips  were  planted  last  spring  to  supply  mate- 
rial for  this  work,  it  will  also  be  feasible  to  give  a  greater 
number  of  members  of  a  family,  and  by  rendering  the 
work  correspondingly  complex  increase  its  educative 
value. 

Results.— In  the  nine  years  of  work  outlined,  some  330 
lessons  on  plants  have  been  planned,  at  an  expense  of  130 
hours  of  the  child's  time  (one  seventieth  of  his  school 
hours).     He  is  now  able  to  pass  a  thoroughly  intelligent 


332  SYSTEMATIC  SCIENCE  TEACHING. 

examination  in  botany,  and  has  also  been  trained  and  de- 
veloped in  other  and  highly  desirable  ways. 

Comparing  this  with  the  ordinary  half  year  of  work 
on  the  subject  in  the  high  school,  after  the  innate  love 
of  childhood  has  been  lost  through  unsympathetic  sur- 
roundings in  the  grades,  we  find  him,  under  the  most 
favorable  circumstances  of  laboratory  teaching,  spending 
over  two  thirds  or  more  as  much  time  in  gathering  a 
hurried  and  technical  knowledge  of  the  subject,  vastly 
inferior  in  scope  and  thoroughness,  and  which  in  large 
measure  lacks  the  developing  power  of  this  systematic 
and  progressive  work. 

The  interrelations  of  things  have  been  shown,  and 
further  and  more  formal  study  of  plant  life  will  be  pleas- 
urable, and  productive  of  results  which  without  this  ele- 
mentary work  would  be  only  attained  after  long  and 
painful  effort  to  correct  the  paralysis  of  neglect  and 
opprobrium.  Other  work  has  been  relieved  and  light- 
ened. By  a  study  of  every-day  surroundings  the  mental 
powers  have  not  only  been  trained  and  "correspond- 
ences "  increased,  but  the  possibilities  of  the  common- 
place have  been  demonstrated,  and  a  pure  and  ennobling 
avocation  opened  for  choice.  If  these  be  true,  no  other 
commendation  of  well-planned  elementary  science  work 
is  needed. 


STEP  XLVIL— OTHER  SYSTEMS  THAN  OURS. 

The  object  of  this  step  is  to  continue  the  mental  train- 
ing of  Step  XLII  by  a  consideration  of  steUar  distances 
and  magnitudes.  Incidentally  it  will  add  to  and  widen 
the  ennobling  conceptions  of  the  material  universe,  of 
which  we  form  so  small  a  part. 

The  time  should  be  at  opportune  dates  through  the 
year.  Some  class  work  and  much  out-of-door  observing 
will  be  needed. 

Apparatus  has  already  been  indicated  in  preceding 
star  work. 

Preparation  of  the  Teacher.-— Much  the  same  as  in 
XLII,  which  should  have  left  a  keen  appetite  for  "  more  " 
on  the  part  of  teacher  and  pupils.  Ball's  Story  of  the 
Heavens  is  a  recent  and  helpful  book.  While  not  up  to 
date  in  figures  and  conclusions,  Burr's  Ecce  Coelum  has 
never  been  superseded  as  an  inspiring  book,  and  chap- 
ter V  could  well  be  made  the  basis  of  this  step,  reading 
it  in  the  class  and  testing  and  correcting  its  statements 
by  more  recent  books. 

The  Lessons. 

So  much  will  depend  on  the  individuality  and  per- 
sonal inspiration  of  the  teacher  that  it  is  with  great  diffi- 
dence that  a  venture  is  made  to  say  how  these  shall  be 
given.  Personal  experience  may,  however,  prove  sug- 
gestive. 

1.  Review  XLII  by  thorough  questioning  and  lead 
up  to, 

333 


334  SYSTEMATIC  SCIENCE  TEACHING. 

2.  Is  this  the  only  planetary  system  ? 

3.  What  is  the  center  and  life  of  this,  the  solar  sys- 
tem ?     (The  sun.) 

4.  What  holds  the  unsupported  planets  in  their  or- 
bits ?    (Attraction  of  the  sun.) 

5.  Through  what  distances  does  gravitation  act  ? 
(All.) 

6.  As  a  whole,  what  does  our  system  rest  upon  ? 
(Nothing.) 

7.  What  must  be  its  state  if  unsupported  ?  (In  mo- 
tion.) 

8.  Toward  what  ?  (It  is  the  purpose  of  this  step  to 
consider  some  of  the  possibilities  in  the  case.) 

9.  What  is  parallax  f    (See  Todd,  p.  234.) 

10.  How  far  is  the  moon  from  us  ?  What  motion  has 
she? 

11.  How  far  is  the  sun  ?  What  motion  has  he  ? 
(Young,  pp.  458-460). 

12.  How  far  to  the  nearest  star  ?    (Todd,  p.  435,  etc.) 
How  far  to  the  base  line  ? 

How  far  to  the  angle  opposite  ? 

(Get  the  radius  of  some  slight  curve  in  railway  or 
driveway  from  the  engineers  and  lay  off  the  length  of 
one  second  of  arc.  The  small ness  of  this  will  aid  in  the 
conception  of  the  vast  distance  it  is  desired  the  class 
shall  attempt  to  realize.  Add  the  illustrations  of  the 
books,  placing  this  important  matter  in  many  lights.) 

13.  The  "  light  year  "  unit  of  measure. 
How  far  does  light  go  in  a  second  ? 
From  the  moon  ?    From  the  sun  ? 

From  Alpha  Centauri  ?  Polaris  ?  Arcturus  ?  (see 
Todd,  p.  439). 

14.  If  one  could  see  events  on  the  earth  at  such  dis- 
tances what  would  he  now  see  at  Arcturus  ?  (The  events 
of  one  hundred  and  sixty  years  ago.) 

At  Vega  in  the  Harp  ?    At  Altair  in  the  Eagle  ? 


OTHER  SYSTEMS  THAN  OURS.  335 

15.  What  is  beyond  these  stars  whose  distance  is 
known  ? 

16.  What  is  the  universe  ? 

17.  What  is  man  f 

Books  of  reference  should  be  fully  supplied  and  much 
used.  Encourage  comparative  work  on  special  points, 
finding  all  that  is  said  by  available  authorities  and  sum- 
ming up  the  matter  in  writing.  Reports'  also  should  be 
had  of  any  individual  work  done,  from  the  making  of  a 
telescope  to  the  learning  of  the  constellations.  This  will 
give  dignity  to  and  greatly  stimulate  the  original  ele- 
ment, which  is  so  much  to  be  desired. 

Constellations. — Among  those  so  far  omitted  I  would 
especially  advise  finding  Orion  and  the  Great  Dog  in  the 
winter,  and  the  Arrow,  Eagle,  and  Dolphin  in  the  summer. 

Portfolios  of  constellations  and  maps  were  suggested 
in  Step  VII.  These  should  liow  be  called  for  and  perhaps 
placed  on  exhibition,  due  credit  being  given  for  all  good 
work. 

Close  the  work  by  some  public  celebration,  so  arranged 
that  the  different  grades  can  participate  in  entertaining 
visitors  with  what  they  have  made  and  learned,  the  cen- 
tral idea  being  not  to  show  off^  but  to  use  what  we  have 
for  the  pleasure  of  others. 

Results. — For  nine  years  a  sympathy  and  wise  exer- 
cise has  trained  the  natural  curiosity  of  the  child. 

In  some  190  exercises,  occupying  between  sixty  and 
seventy  hours  of  his  school  time,  has  a  healthy  interest 
in  noble  things  been  cultivated.  Some  of  the  results,  if 
the  work  is  patiently  and  progressively  done,  will  be 

Increased  ability  to  think  to  a  conclusion. 

Helpful  concepts  for  physics  and  geography,  etc. 

Discernment  of  the  interrelation  of  things. 

The  scientific  method  of  handling  questions. 

Improved  eyesight. 

A  knowledge  of  his  own  powers  and  preferences. 


336  SYSTEMATIC  SCIENCE  TEACHING. 

Resourcefulness  for  healthy  avocation. 

Less  affinity  for  evil  through  the  added  affinity  for 
good. 

A  healthy  mental  appetite  for  knowledge  which  will 
cause  him  to  take  up  the  formal  study  of  astronomy  or 
related  subjects  with  ease  and  facility. 

Can  one  one-hundred-and-fortieth  of  the  school  time 
of  a  fifteen-year-old  child  be  spent  to  better  advantage  ? 


STEP  XLVIII— ROCK  MAKmG—iConti7iued). 

Organic  Agencies  and  Metamorphism. 

The  object  of  these  final  lessons  along"  the  line  of  in- 
organic nature  differs  in  no  respect  from  those  given  for 
Kock  Making.  The  life  element  will  be  introduced,  and 
we  shall  show  how  plants  and  animals  have  aided  in  pre- 
paring the  earth  for  man,  as  well  as  the  changing  (meta- 
m Orphic)  effects  of  heat,  etc.,  on  the  fragmental  rocks 
before  studied. 

Time  needed  will  be  about  fifty  lessons  of  thirty  min- 
utes each. 

Material. — This  has  been  so  selected  as  to  conduct  the 
pupil  through  the  continuation  of  the  geological  story 
by  a  series  of  concrete  illustrations. 

Brief  Outline. 

1.  Modern  shells,  corals,  etc. 

2.  Rocks  formed  by  or  containing  ancient  forms  of 
animal  life. 

3.  Modern  allies  of  fossil  plants. 

4.  Eocks  formed  of  or  containing  ancient  forms  of 
plant  life. 

5.  Metamorphic  agencies  illustrated. 

6.  Metamorphic  rocks. 

As  in  Rock  Making,  all  specimens  given  to  the  pupil 
should  have  numbers  on  them,  and  as  some  of  the  former 
series  will  be  needed  in  this,  the  numbers  are  made  con- 
secutive. 

23  337 


338  SYSTEMATIC  SCIENCE  TEACHING. 

29.  Shells  of  oyster  and  clam  (in  mated  pairs). 

30.  Univalve  shells  with  and  without  a  canal. 

31.  Specimen  of  coral. 

32.  Limestone  with  fossil  shells. 
Limestone  with  fossil  coral. 

Slide  or  illustration  of  foraminifers. 

33.  Chalk. 

Slide  or  illustration  of  magnified  chalk. 

Nummulitic  limestone. 

Slide  showing  sponge  spicules. 

Slide  showing  polycistines. 

Slide  showing  diatoms. 

Diatomaceous  earth. 

Slide  of  diatomaceous  earth. 

Slide  showing  section  of  flint. 

34.  Flint. 

35.  Chert. 

36.  Lichens  (mounted). 

37.  Ferns  (mounted). 

38.  Lycopods  (mounted). 

39.  Equisetums  (sterile  and  fertile  plants). 

40.  Conifers  (wood,  leaves,  and  fruit). 

41.  Sphagnum. 

42.  Peat. 

Mud  (black). 

43.  Black  shale. 

44.  Soft  coal  showing  plant  remains. 
Fossil  calamite. 

Fossil  of  fern. 

Fossil  of  lepidodendron. 

Examples  of  vein  structure  in  rocks. 

Siliceous  tufa. 

45.  Melaphyre. 

46.  Gypsum. 

47.  Amygdaloid. 
Agate. 


ROCK  MAKING.  339 

48.  Quartzite. 

49.  Slate. 

50.  Mica  schist. 

51.  Hornblende  schist. 

52.  Chlorite  schist. 

53.  Talcose  schist. 

54.  Gneiss. 

55.  Granite. 

56.  Hematite. 

57.  Magnetite. 

58.  Marble. 

59.  Serpentine. 

60.  Anthracite. 
Petroleum  (crude). 
Graphite. 

Boxes  or  trays  for  each  pupil  had  best  be  of  wood,  as 
suggested  in  Rock  Making. 

Where  and  how  to  get  this  Material— Gather  all  you 
can,  and  buy  what  you  must.  Enough  of  the  numbered 
specimens  should  be  gathered  so  that  each  pupil  may 
have  a  set.  The  illustrative  material  should  be  chosen  so 
that  a  whole  class  can  see  it  from  the  desk.  Illustrative 
charts  on  zoology  or  geology  will  also  aid,  and  will  tide 
the  teacher  over  the  "missing  links"  in  her  series  of 
specimens,  as  many  things  can  not  be  bought,  nor  can 
they  be  found  at  short  notice,  and  no  one  should  feel 
discouraged  if  everything  is  not  on  hand  for  the  first 
class ;  year  by  year  will  add  to  the  material  an  earnest 
teacher  w^ill  gather. 

I  have  suggested  several  slides  for  the  microscope. 
These  can  be  exhibited  at  recesses  or  after  school.  Should 
they  not  be  obtainable,  bright  pupils  could  put  drawings 
enlarged  from  geologies  and  zoologies  on  the  board,  or, 
better,  on  thin  cloth  (in  ink),  so  as  to  preserve  them.  The 
shells  can  be  easily  had  in  cities,  and  the  plants  can  be 
gathered,  dried  under  pressure,  and  mounted  on  cards. 


340  SYSTEMATIC  SCIENCE  TEACHING. 

Cost. — After  deducting  those  specimens  already  on 
hand,  as  minerals,  those  which  can  be  gathered  and 
found,  only  seventeen  to  twenty  sets  of  thirty  specimens 
will  have  to  be  bought,  and  they  will  cost  about  $15. 
For  the  slides  and  illustrative  specimens  get  good  ones, 
if  you  buy,  even  though  only  part  can  be  bought  at  a 
time. 

Store  in  boxes  continuing  the  plan  suggested  for  the 
specimens  in  Rock  Making. 

Notebooks  should  be  kept.  By  choice  continue  the 
one  on  Rock  Making. 

Literature. — A  good  work  on  zoology  and  botany,  with 
pictures  of  fossils,  will  be  useful  additions  to  those  books 
suggested  in  Step  XLIV. 

Preparation  of  the  Teacher.— Nothing  need  be  added 
to  what  was  said  under  Rock  Making.  The  great  thing 
is  to  continually  keep  yourself  in  the  position  of  one  who 
has  seen  some  interesting  thing  and  is  showing  it  to 
others.  You  will  not  fail  in  that  case  of  a  sympathetic 
class. 

The  Lessons. 

I  shall  take  it  for  granted  that  most  of  the  class  have 
had  the  lessons  on  Earth  Making,  and  that  many  have 
helped  order,  unpack,  number,  and  put  away  the  speci- 
mens bought;  have  washed  the  shells,  pressed  and 
mounted  the  plants,  cracked  up  the  rocks  gathered ; 
hunted  in  coal  heaps  for  black  shale  and  coal  with  plant 
remains  ;  have  dug  peat  and  mud  in  swamps,  and  copied 
cuts  of  magnified  chalk,  diatoms,  and  the  exquisite  fo- 
raminifers  and  polycistines. 

Such  exercise  is  conducive  to  a  warm  interest,  and 
your  class  is  now  ready. 

1.  Review  Earth  Making  to  freshen  up  the  matter.  I 
give  some  of  the  questions  which  my  notes  show  as  hav- 
ing been  used. 


ROCK  MAKING.  341 

Wrap  an  entire  set  of  specimens  of  Rock  Making  in 
papers,  and  add  such  things  as  glass,  bottles  of  water,  air, 
carbonated  water,  lime  test,  iron  test,  etc.,  making  as 
complete  a  set  of  illustrative  specimens  as  possible.  Also 
gather  pictures  of  volcanoes,  icebergs,  glaciers,  deltas, 
filling  of  lakes,  divers  in  armor,  etc. 

Distribute  these  among  the  class  just  as  they  happen  to 
come,  and  let  each  one  open  his  parcel  and  have  it  ready 
to  describe  when  the  time  comes  in  your  questioning. 

What  idea  did  Laplace  have  about  this  earth  and  the 
solar  system  ? 

How  did  the  earth  originate  ? 

How  the  moon  ? 

Give  some  idea  of  the  cooling  of  the  earth. 

Why  flattened  at  the  poles  ? 

What  are  volcanoes  ?     Show  pictures. 

Describe  an  eruption. 

What  rocks  have  any  of  you  that  were  thrown  or 
flowed  out  ? 

Show  me  the  dike  rocks  you  have.    How  recognized  ? 

What  rocks  that  may  have  been  part  of  the  original 
crust  ?    Why  ? 

Hold  up  pumice,  and  tell  me  about  it.  (So  on  through 
the  first  eight  rocks  of  Step  XLIV.) 

Who  has  a  cracked  rock  ?    How  made  ? 

Show  me  lichens  on  a  rock.  What  can  you  tell  me 
about  them  ? 

Show  and  tell  me  facts  about  a  rock  scaling  off. 

Explain  a  ''  compound  bar." 

Who  has  a  rock  containing  pyrite  ?    Why  injurious  ? 

What  are  the  cubes  of  clay  to  show  ? 

What  causes  the  rusting  of  pyrite  ? 

What  may  the  swelled  iron  sulphate  show  ? 

The  misshapen  brick  ? 

The  red  clay  ? 

The  gray  clay  ? 


342  SYSTEMATIC  SCIENCE  TEACHING. 

Show  a  picture  of  a  glacier  to  the  class,  and  de- 
scribe it. 

Show  picture  of  iceberg  and  describe. 

What  caused  this  ice  to  form  ? 

What  can  you  tell  of  its  motion  ? 

Where  do  the  Alpine  glaciers  end  ? 

What  kind  of  material  is  found  at  the  end  ? 

What  are  the  signs  of  ancient  glaciers  ? 

Where  do  the  arctic  glaciers  end  ? 

What  do  they  carry  on  them  ? 

What  causes  them  to  melt  ?  Where  ?  What  is 
formed  ? 

How  is  the  gravel,  sand,  and  clay  gathered  ? 

How  sorted  ? 

Describe  the  filling  up  of  a  lake. 

How  is  a  delta  made  ? 

Where  did  the  scale  in  the  teakettle  come  from  ? 

Tell  about  Mammoth  Cave. 

How  was  it  made  ? 

What  are  stalactites  ? 

What  are  stalagmites  ? 

Mexican  onyx  ?    What  causes  the  brownish  veins  ? 

Where,  and  how,  was  oolite  made  ? 

What  does  the  crust  on  lime  water  illustrate  the  form- 
ing of  ? 

Where  was  all  the  iron  originally  ?  (Scattered 
through  rocks,  and  next  in  soils,  etc.) 

How  was  it  brought  into  the  great  beds  we  now  find  ? 

Where  is  bog  iron  found  ? 

Where  will  siderite  form  ? 

What  is  one  way  gypsum  seems  to  have  formed  ? 

Rock  salt  ? 

What  may  a  piece  of  house  plaster  illustrate  ? 

How  were  conglomerates  made  ? 

How  red  sandstone  ? 

How  does  gray  sandstone  differ  ? 


ROCK  MAKING.  343 

How  was  shale  made  ? 

Are  these  fragmental  rocks  in  strata  ? 

Now  replace  material  where  it  can  be  seen  and  easily 
got  at. 

2.  Give  limestone  and  coaL 

Here  are  other  rocks  in  strata.  Are  they  made  of 
pebbles?    Of  sand  ?    Of  clay  ?    (No.) 

Let  us  study  about  them. 

Lime  gathered  from  the  sea. 

Give  each  a  clam,  oyster,  or  other  similar  shelL 

Notice  the  structure  and  parts  of  each. 

Test  a  bit  of  broken  shell  in  acid  (HCl).  (Effervesces 
=  COu.) 

Try  the  lime  test.  (NH4HO  4-  ammonium  oxalate  = 
white  precipitate  of  lime.) 

Shells,   then,  are    mostly  made  of ?      (COa  and 

lime.) 

Examine  bits  of  COral  in  the  same  way.  Speak  of 
coral  islands. 

Give  lime  rock  containing  fossils,  and  examine. 

What  is  another  way  limestone  has  been  made  ? 
(Shells  and  coral.) 

Where  did  these  animals  get  the  lime  ?  (From  their 
food.) 

How  did  much  of  the  lime  get  in  the  ocean  ?  (COa 
water  of  rivers.*) 

*  Care  must  be  exercised  in  the  use  of  proper  words  in  this 
connection,  as  the  greatest  confusion  (and  error,  I  think)  exists 
in  most  references  to  the  growth  of  corals  and  mollusks.  They 
are  by  many  writers  said  to  get  their  lime  (for  coral  and  shell) 
from  the  sea  water.  This  I  deem  very  misleading.  Plants  seem 
the  only  beings  able  to  assimilate  mineral  matter.  Even  the 
lime,  iron,  etc.,  which  may  be  in  solution  in  the  water  an  animal 
takes  in,  does  not  appear  to  be  utilized  as  food,  to  become  part  of 
the  animal.    The  plant  alone  can  do  that,  and  then  the  animal 


344  SYSTEMATIC  SCIENCE  TEACHING. 

Show  slide  or  drawing  of  foraminifers.  Tell  of  the 
deep-sea  ooze  now  found  (Le  Conte,  p.  453,  or  Dana,  p. 
131,  etc.),  and  then  give  specimen  of  chalk  and  compare 
it  with  slide  or  drawings  showing  how  it  appears  under 
the  microscope. 

Nummulitic  limestone  will  be  of  interest  (see  Le  Conte, 
p.  485),  from  the  great  abundance  and  curious  shape  of 
the  little  shells. 

How  many  ways  have  we  now  found  of  making  solid 
rock  from  the  lime  in  solution  f  (By  COa,  coral,  shells 
of  moUusks,  and  foraminifers.) 

Call  attention  to  the  immense  beds  of  limestone  and 
chalk  which  are  found,  and  try  to  give  some  idea  of  the 
work  these  minute  animals  have  done  in  mountain 
making. 

Silica  gathered  from  the  water. 

Next  show  slides  of  sponge  spicules  and  polycistines. 
These  are  of  silica,  although  most  other  animals  have 
limy  skeletons. 

Plants  that  have  helped  are  the  minute  diatoms  (show 
slide).  These  little  plants,  having  skeletons  of  silica,  live 
in  the  sea,  and,  dying,  drop  their  tiny  shields  among  the 
chalk  shells,  sponge  spicules,  and  polycistine  shells  on 
the  deep-sea  floor,  where  they  aid  in  making  the  thick 
beds  of  chalk. 


eats  and  appropriates  the  mineral  matters  needed  for  its  growth 
from  that  stored  in  the  plant. 

We  do  not  find  animal  life  preceding  plant  life,  and  herbiv- 
orous (plant-eating)  animals  must  have  existed  before  carnivo- 
rous (flesh  eaters). 

The  sea  abounds  in  minute  forms  of  vegetable  life  (Dana,  p. 
135),  and  on  these  feed  the  minute  animals  which  serve  as  food 
for  the  corals  and  shell-bearing  mollusks.  Hence  not  only  guard 
against  calling  the  coral  animal  " an  insect"  or  talking  of  its 
"building"  islands,  but  also  avoid  even  the  inference  that  they 
take  the  lime  directly  from  the  water. 


ROCK  MAKING.  345 

At  times  beds  of  diatoms  are  found,  forming  diatoma- 
ceous  earth  (show  specimen  of  the  earth,  and  read  of 
them  in  Le  Conte,  p.  484,  and  Dana,  pp.  135,  496,  633, 
634). 

Flint  and  Chert. — These  minerals  are  found  in  the 
shape  of  nodules  in  beds  of  limestone  and  chalk  (see 
Le  Conte,  p.  452,  ff.). 

When  thin  slices  are  examined  under  the  microscope 
they  often  show  the  fossil  skeletons  of  minute  diatoms, 
sponge  spicules,  etc.,  scattered  through  the  hard  flint. 
How  could  they  have  got  there  ? 

It  is  supposed  that  alkaline  water  has  dissolved  the 
minute  shields  of  diatoms,  etc.,  scattered  through  the 
chalk  or  limestone,  and  deposited  the  silica  again  in  these 
nodules  of  flint  and  chert,  somewhat  as  the  iron  has 
been  gathered  from  the  sands  and  gravels. 

Higher  plants  than  these  diatoms  have  also  done 
much  rock  making,  but  in  a  very  different  way. 

Living  plants  allied  to  these  ancient  ones  will  be  first 
examined.  Give  specimens  of  lichens,  ferns,  lycopods 
(club  moss),  equisetum,  and  conifers. 

Review  previous  botanical  work  on  these,  learning 
their  characteristics,  mode  of  growth,  and  habitat. 

Where  do  most  of  these  grow  ?  (Wet,  marshy 
ground.) 

Will  they  all  burn  when  dry  ? 

What  is  it  in  them  that  burns  ?  (Carbon  and  hydro- 
gen.) 

Where  does  the  plant  get  its  carbon  ?  (see  Step  XXIII, 
Morning-Glory).     (From  the  air.) 

In  what  shape  must  carbon  be  to  exist  as  a  gas  ? 
(CO,.) 

Do  all  plants  when  burned  leave  an  ash  f    (Yes.) 

What  color  is  it  when  well  burned  ?     (Gray.) 

Where  did  the  ash  come  from  ?  (The  "  earth  food  " 
of  the  soil.) 


346  SYSTEMATIC  SCIENCE  TEACHING. 

What  besides  air  and  earth  food  do  plants  need  for 
growth  ?    (Heat  and  light.) 

How  will  plenty  of  heat  and  moisture  (as  in  the  trop- 
ics) affect  the  rate  of  growth  ?     (Rapid.) 

Will  the  results  of  this  rapid  growth  be  spongy,  or 
dense,  tissues  ? 

Compare  a  cornstalk  and  hickory  stick.  (Spongy  and 
soft.) 

Are  the  plants  we  have  in  hand  most  like  the  com,  or 
the  hickory  ? 

Are  they  then  suited  to  rapid  growth  ?    (Yes.) 

Do  they  bear  bright  -  colored  or  fragrant  flowers  ? 
(No.) 

Do  they  bear  spores,  or  true  seed  f  (Only  the  pine  has 
a  true  seed.) 

Are  these  spores  few,  or  many  ?    {Very  numerous.) 

Where  does  a  post  or  pile  rot  most  quickly  ?  At  sur- 
face of  ground  or  water.) 

How  about  the  portion  always  wet  ?  (Decays  little, 
if  any.) 

Can  you  give  any  illustrations  of  this  ?  (Cedars  fallen 
in  swamps,  water-logged  wood,  remains  of  trees,  etc.,  in 
peat  swamps  and  deltas  ;  see  Le  Conte,  pp.  133-136.) 

What  is  a  peat  swamp  ?  Of  what  plant  is  peat  mostly 
formed  ? 

What  family  of  plants  does  sphagnum  belong  to  ? 
(Mosses.) 

Are  these  mosses  found  among  the  coal  plants  ? 
(No.) 

What  do  most  plants  stand  and  grow  in  ?     (Soil.) 

What  makes  soil  black  f  (Decay  of  the  plants  that 
have  grown  on  it.) 

Where  did  these  pieces  of  black  shale  (No.  43)  come 
from  ?     (Coal  bin.) 

How  did  they  get  among  the  coal  ?  (Shale  is  found 
below  all  coal  seams.) 


ROCK  MAKING.  347 

Who  can  think  what  it  was  once  ?    (Earth.) 

When  burned  in  the  furnace  it  becomes ?  (Whit- 
ish.) 

What  colors  it  black  ?    (Carbon.) 

CoaL— Above  it  lies  a  bed  of ?    (Coal.) 

See  this  piece  of  coal.  What  caused  these  lines  and 
impressions  on  it  ?     (Plants.) 

Here  is  a  bit  of  coal  magnified  (Le  Conte,  p.  341,  or  a 
slide). 

What  does  the  coal  seem  to  have  been  made  of  ? 
(Plants.) 

How  are  stratified  rocks,  shale,  sandstone,  coal,  etc., 
formed  ?     (In  water.) 

Now  show  pictures  and  fossils  of  the  coal  plants  and 
period,  and  then  rapidly  run  over  again  the  series  of 
questions  on  living  plants  and  see  how  much  light  they 
shed  on  the  formation  of  coal. 

What  fossil  does  the  modern  fern  most  resemble  ? 
(The  ancient  fern  found  in  coal.) 

Which  fossil  the  lycopod  ?     (Lepidodendron.) 

Which  the  equisetum  ?     (Calamites.) 

These,  then,  were  the  plants  largely  concerned  in 
making  coal. 

Where  did  the  carbon  come  from  ?     (The  air.) 

If,  as  Laplace  teaches,  the  earth  were  in  a  melted. con- 
dition, where  would  all  the  carbon  now  in  trees,  coal, 
etc.,  be  ?    (In  the  air  as  COa.) 

Could  man,  or  the  air-breathing  animals,  live  in  such 
air  ?     (No.) 

What  way  did  the  limy  water  of  the  early  oceans  re- 
move the  CO2  ?     (Made  limestone.) 

What  way  do  we  next  find  to  further  purify  the 
air  ?  (Plants  decomposing  the  COa,  keeping  the  carbon 
and  returning  the  oxygen.) 

What  do  we  find  overlaying  the  coal  seams  ?  (Shale 
and  other  stone.) 


34:8  SYSTEMATIC  SCIENCE  TEACHING. 

Of  what  use  was  this  covering  up  ?  (Compressed  the 
soft  vegetable  fiber  into  compact  coal  and  prevented 
waste.) 

It  is  very  expensive  and  difficult  to  dig  as  deep  as  we 
do  for  coal. 

What  advantage  is  there  in  such  a  covering  ?  (Pro- 
tected from  burning  up.) 

Metamorphio  Agencies  and  their  Effects.* 

We  have  noticed  the  proofs  that  the  earth  was  once 
much  hotter,  and  consequently  larger,  than  it  is  now. 
As  it  cooled  the  rocky  outer  crust  would  be  obliged  to 
continually  adjust  itself  to  the  contraction  of  the  heated 
interior.  t 

Would  these  changes  be  sudden,  or  very  gradual  ? 
(Gradual.) 

Would  the  rigid  outside  be  too  large,  or  too  small  ? 
(Too  large.) 

What  shape  was  the  crust  ?  (Like  a  hollow  globe, 
everywhere  arched.) 

How  do  the  stones  in  an  arch  distribute  the  weight 
on  them  ?  (By  thrusting  outward  as  well  as  downward. 
The  stones  at  the  top  have  the  most  outward  thrust, 
and  those  at  the  ends  of  the  arch  the  most  downward 
thrust.) 

Would  this  pressure  in  a  globe  be  chiefly  a  down,  or  a 
side-to-side  (lateral),  thrust  ?    (Lateral.) 

Now  think  of  this  with  care. 

What  would  result  from  this  tremendously  heavy 
crust  slowly  adapting  itself  to  the  contracting  interior  ? 
(Enormous  pressure,  resulting  in  a  wrinkling  of  the 
crust,  with  the  necessary  cracking  and  slipping  of  the 
rocks.) 

As  this  land  slowly  came  near  the  surface  of  the 

*  See  Step  XLII,  §  12,  etc. 


ROCK  MAKING.  349 

oceans,  what  would  the  waves  do  ?  (Grind  rocks  to 
pieces.) 

As  the  land  arose  abo^e  the  sea,  what  would  carry  on 
the  work  of  soil  making  ?    (Rain,  sun,  atmosphere,  etc.) 

Where  would  much  of  these  fragments  go  ?  (Wash 
into  the  sea.) 

So,  for  vast  ages,  we  believe,  this  first  formed  land 
went  on  slowly  rising  and  at  the  same  time  being  cut 
down  by  the  waves,  rain,  air,  and  other  agencies,  and  the 
ocean  filled. 

Through  the  cracks  formed  in  the  rocks  must  have 
welled  up  great  floods  of  lava.  Meeting  the  waters  of  the 
ocean  in  some  cases — what  would  happen  to  the  lava  ? 
(It  would  crack  into  pieces  and  the  waves  quickly  pul- 
verize it.) 

If  it  flowed  out  upon  the  land  ?  (It  would  rapidly 
disintegrate,  and  be  added  to  the  deep  beds  of  sediment 
in  the  ocean.) 

While  in  these  ways  the  first  continents  were  being 
torn  down,  a  change  was  taking  place  in  the  rocky  bed 
of  the  oceans,  over  which  all  this  gravel,  sand,  and  mud 
had  been  piled. 

As  we  dig  down  into  the  earth  how  does  the  tempera- 
ture vary  ?    (Becomes  hotter.) 

If  we  cover  up  the  earth,  as  in  glacier  making  ? 
(The  heat  increases.) 

Now,  as  thousands  of  feet  of  sediment  are  carried  by 
the  water  and  piled  in  wet  beds  on  the  ocean  floor, 
how  about  the  temperature  of  the  original  rocky  bot- 
tom ?    (Rises.) 

As  these  beds  become  thicker  the  temperature  must 
rise  till  at  last  the  rocky  bottom  softens. 

Here,  off  the  coasts  of  the  land,  we  then  have  a  soft- 
ened rocky  bottom  overlaid  by  wet  beds  of  sediment, 
all  under  the  same  tremendous  side-to-side  squeeze  or 
thrust. 


350 


SYSTEMATIC  SCIENCE  TEACHING. 


Can  you  think  what  will  happen  ?  (These  soft  beds 
will  be  slowly  mashed  together  from  side  to  side.) 

Slate  has  been  made  in  this  way  from ?    (Shale.) 

As  their  horizontal  extent  is  compressed,  what  must 
happen  to  their  thickness?    (Increases.) 

And  so,  as  time  goes  on  and  the  old  land  is  washed 
into  the  sea,  a  new  continent  or  mountain  chain  slowly 
rises  from  the  waters. 

Where  will  this  new  land  lie  ?  (Along  the  shores  of 
the  old  land.) 

What  rocks  will  it  contain  ?  (Conglomerates,  sand- 
stones, shales,  slates,  and  limestone.) 

As  these  emerge,  how  will  they  in  turn  wear  away  ? 
(Waves,  rain,  etc.) 

The  earth's  crust  is  growing  smaller  all  the  time,  and 
so  the  whole  surface  can  not  be  rising  at  once.  Hence, 
as  this  new  wrinkle  grows,  what  must  happen  to  the  old 
wrinkle  ?    (Stops  rising,  or  perhaps  sinks.) 

Will  the  old  or  the  new 
land,  in  the  end,  be  high- 
est ?    (New.) 

How  does  it  come  to  be 
that  so  many  mountain 
chains  are  parallel  to 
each  other  and  the  coast 
line  ?  (Successive  emer- 
gences along  the  old 
coasts.) 

What  will  cause  most 
of  the  ridges,  peaks,  and 
valleys  ?    (Erosion.) 

Wonderful      as      this 
mountain  making  is,  there 
are  other  important  results  from  the  same  causes. 

Veins. — Hot  water,  probably  from  the  wet,  heated 
beds  of  sediment  we  have  spoken  of,  is  constantly  find- 


FiG.  10.— Araygdule  filling 
agate. 


ROCK  MAKING. 


351 


ing  its  way  through  the  cracks  made  by  the  wrinkling  of 
the  crust.  This  heated  water  often  contains  acids  or 
alkalies  in  solution,  which  enables  it  to  dissolve  quartz  or 
metals  from  the  beds  it  was  in,  or  the  walls  of  the  crack 
through  which  it 
flows. 

Melaphyre  is  a 
rock  which  has 
been  changed  by 
hot  water. 

Amygdaloid  is 
a  rock  whose  cellu- 
lar cavities  have 
been  filled  from 
the  minerals  re- 
moved by  such 
water.  What  rock 
was  it  once  ? 
(Lava.) 

Agates  are  large 
amygdules  of  dif- 
ferently colored 
quartz  left  by  such 
water  as  it  circulated  through  and  cooled  in  cracks  and 
cavities. 

Geodes  are  cavities  in  rock  bathed  in  waters  contain- 
ing silica  from  which  the  beautiful  crystals  have  grown. 

Gypsiun  sometimes  is  found  among  limestone,  and  it 
is  supposed  has  been  caused  by  acid  water  turning  the 
calcium  carbonate  to  calcium  sulphate. 

Geysers  are  caused  where  water  containing  silica  comes 
to  the  surface  as  a  spring.  Little  by  little  the  silica  is 
deposited  in  the  crack  and  about  the  opening  till  it  is  so 
closed  that  the  circulation  (convection)  is  impeded  and 
the  water  forced  violently  out  at  intervals  (see  Le  Conte, 
pp.  94-103). 


Fig.  11. — Vein  filled  with  quartz. 


352 


SYSTEMATIC  SCIENCE  TEACHING. 


Siliceous  tufa,  or  geyserite,  is  made  about  hot  springs 
and  geysers.  As  time  goes  on  these  cracks  through 
which  the  water  rises  become  filled  up  by  the  formation 
of  a  vein.     (Class  draw  Figs.  10,  11,  and  12.) 

Not  only  do  these  contain  agate  and  many  of  our 
most  beautiful  crystals,  but  they  also  contain  much  of 

the  lead,  copper,  gold, 
silver,  tin,  and  other 
valuable  metals  and 
minerals,  so  that  veins 
are  of  great  importance 
to  us.  Some  of  these 
things  are  illustrated  in 
the  diagrams. 

Earthquakes. — Glass 
is  brittle,  still  a  rod  or 
sheet  of  it  will  bend 
some  before  the  sudden 
snap  with  which  it 
breaks.  So  rock,  in  the 
crumpling  of  the  crust, 
keeps  giving  a 
little  to  the 
strain,  and  at 
last  suddenly 
cracks  with  a 
shock  which  we 
call  an  earth- 
quake. As  to  the  terrible  effects  of  such  shocks  the 
books  will  tell. 

Faults.— When  these  cracks  occur,  one  side  or  the 
other  is  apt  to  slip  up  or  down.  (Draw  a  diagram  of 
one  from  some  work  on  geology.)  These  are  very  per- 
plexing to  miners,  as  they  find  a  coal  seam  or  ore 
vein  suddenly  ending,  and  where  it  has  gone  to  is  the 
question. 


l)fbgb 


Fig.  12.— Metalliferous 
vein. 


Galena. 
J  Baryta. 
feS:^-:^  Feldspar. 
Wall  rock. 


ROCK  MAKING.  353 

Heat. — As  the  rocky  layers  slip  over  each  other  not 
only  do  they  get  displaced,  but  what  also  results  from 
rubbing  things  together  ?     (Heat.) 

If  the  rubbing  is  done  by  very  heavy  masses,  how 
about  the  heat  ?     (Very  great.) 

This  will  then  heat  the  rocks  near  the  crack. 

Dikes. — At  times  melted  rock  flows  up  through  the 
cracks  in  the  rock  instead  of  hot  water  (see  diagram  1  in 
Step  XLIV).  This  melted  rock  may  be  forced  between 
beds  of  limestone  or  shale  or  flow  out  upon  the  surface. 
In  either  case,  what  will  happen  to  the  adjoining  rocks  ? 
(Be  heated.) 

Just  where  this  melted  rock  comes  from  we  do  not 
know,  but  have  many  reasons  for  thinking  that  the  cook- 
ing of  the  lower  sediments  in  the  very  hot  water  which 
must  be  there  so  softens  the  sandstones  and  shales  as  to 
form  a  thick  liquid,  which  the  immense  pressure  of  the 
overlying  beds,  and  perhaps  deep  oceans,  forces  up 
through  the  cracks  as  lava.  However  this  may  be.  we 
do  find  that  crystallization  can  take  place,  and  the  frag- 
mental  beds  become  changed  to  crystalline  rock,  or  are 
firmly  cemented  by  the  solutions  of  mineral  in  the  water. 

Metamorphism. 

All  this  dissolving  out  or  filling  in  by  the  heated  wa- 
ter, and  heating  by  sliding,  by  dikes,  or  from  the  interior, 
causes  a  change  in  the  rocks,  and  such  changed  rocks  are 
called  metamorphic. 

Some  common  illustrations  will  aid  in  understanding 
this. 

Gray  clay,  when  heated,  becomes ?    (Red  brick 

or  tile,  as  the  siderite  in  it  becomes  hematite.) 

Black  shale  or  limestone  burns ?     (Red  or  white, 

according  as  there  is  or  is  not  iron  in  it.) 

Coal,  heated  in  gas  retorts ?    (Becomes  hard,  po- 
rous coke,  tar,  and  gas.) 
24 


354  SYSTEMATIC  SCIENCE  TEACHING. 

Sand,  mixed  with  lime  or  alkali  ?  (Fuses  to  a  glass, 
and  crystallizes  if  slowly  cooled.) 

Give  the  class  the  rest  of  the  specimens. 

Under  these  conditions  of  highly  heated  water  and 
great  pressure,  conglomerates  become  very  firm  and 
hard. 

Sandstones  become ?    (Quartzite.) 

Shales  and  slates  become  (according  to  what  they  con- 
tain) mica,  hornblende,  chlorite  or  talcose  BChists,  each 
known  by  the  principal  mineral  composing  it. 

Are  schists  thick,  or  thin,  bedded  ?    (Thin.) 

If  thick  bedded,  such  rocks  are  called  gneiss. 

If  all  trace  of  bedding  is  gone,  and  they  seem  un- 
stratified,  they  are  called  granite,  syenite,  etc.,  the  same 
as  rocks  we  have  met  before. 

Serpentine  is  formed  by  the  alteration  of  other  min- 
erals, and  when  it  occurs  in  limestone  we  have  the  beau- 
tiful green  veining  of  some  marbles  (verde  antique). 

Limestones  and  dolomites  become  changed  to  crystal- 
line. 

Marbles. — These  are  black  (from  the  charring  of 
organic  matter)  or  brown  (from  limonite)  if  the  heat 
is  gentle  and  water  present,  while  the  dry  heat  from 
dikes  or  friction  turns  the  blacks  to  white  and  browns 
to  red. 

Iron  forms  an  exceedingly  interesting  series  as  seen 
from  this  standpoint.  First  found  scattered  through  the 
rocks  as  a  part  of  the  iron-bearing  minerals  augite,  horn- 
blende, mica,  etc. ;  with  the  decay  of  these  and  the  action 
of  carbonated  water,  it  goes  into  solution  as  siderite,  to 
be  gathered  and  deposited  in  the  same  state  if  organic 
matter  is  present  (peat  bogs,  coal  seams,  and  some  clays), 
or  changed  to  limonite  if  exposed  to  the  air. 

If,  now,  these  masses  of  gathered  ore  are  subjected  to 
heat,  the  siderite  becomes  brown  (limonite) ;  as  the  heat- 
ing continues  and  water  is  driven  off  the  brown  changes 


ROCK  MAKING.  355 

to  red  (hematite) ;  and  if  the  heat  is  greater,  this  finally 
becomes  magnetite,  just  as  iron  occurs  in  lava. 

Coal  also  forms  an  interesting  series. 

The  original  vegetable  matter  is  softened  by  water, 
and  then  the  pressure  aids  in  turning  it  into  beds  of  soft 
coal.  The  heat  of  metamorphism  now  changes  this  into 
the  hard,  lustrous  anthracite  (a  natural  coal),  and  in  the 
process  vast  quantities  of  "  natural  "  gas  are  driven  ofP. 

Petroleum  and  bitumen  may  be  formed  at  the  same 
time,  as  tar  is  in  gas  making ;  but  there  are  reasons  for 
thinking  these  have  come  from  the  heating  of  such 
shales  as  contain  plant  and  animal  remains  (black  shale, 
etc.).  If  the  heat  is  carried  still  higher,  some  of  these 
(anthracite,  petroleum,  bitumen,  etc.)  become  graphite, 
and  the  lustrous,  crystalline  diamond. 

This  will  end  the  course  in  Minerals  and  Rocks. 

Review  of  Bocks. — Wrap  up  a  set  of  the  specimens 
talked  of  and  procure  maps,  pictures,  etc.,  as  suggested  at 
the  beginning  of  this  step,  and  have  a  thorough  review. 

In  preparing  the  questions,  follow  the  order  in  which 
the  material  was  given  and  the  matter  discussed,  intro- 
ducing at  the  proper  place  questions  about  the  things 
familiar  to  the  child  in  every-day  life,  such  as  the  follow- 
ing: 

What  may  have  been  the  cause  of  the  Lisbon  earth- 
quake ? 

Why  are  the  mountains  of  western  North  America  in 
several  nearly  parallel  chains  ? 

Where  does  the  oil  in  our  lamps  come  from  ? 

Give  the  history  of  the  graphite  in  your  pencil  ? 

Of  the  slate  you  write  on  ? 

Why  are  bricks  red  ? 

What  was  this  white  piece  of  clinker  from  the  fur- 
nace ? 

Is  the  marble  of  the  mantel  of  more  interest  to  you  ? 
Why? 


356  SYSTEMATIC  SCIENCE  TEACHING. 

Where  did  the  beautiful  crystals  probably  form  ? 

How  do  crystalline  garnets,  etc.,  come  to  be  in  schists  ? 

Give  us  the  history  of  that  coal  in  the  hod. 

Of  this  diamond.  This  iron  ore.  The  mended  crack 
in  the  stone. 

The  class  might  help  think  of  things  about  them 
which  are  connected  with  lime,  coal,  and  metamorphic 
rocks. 

Review  of  the  Whole  Series  of  Lessons.— The  great 
thing  here  is  to  spread  the  whole  work  out  for  the  encour- 
agement and  help  of  the  pupils  and  their  friends.  If  sev- 
eral grades  or  schools  are  at  work  on  different  steps  at  the 
same  time,  let  each  class  make  up  its  own  exhibit,  but 
have  all  in  one  room,  and  let  the  pupils  have  the  pleas- 
ure of  showing  their  friends  about  and  telling  them  the 
wonderful  things  they  remember.  This  will  be  time 
well  spent,  and  should  be  one  of  the  "events"  of  the 
year,  to  which  the  classes  and  parents  will  look  forward 
with  pleasure. 

Plan  for  Exhibition  of  Work  done  in  Minerals  and 
Rocka— 1.  Table  of  sorted  metals. 

2.  Table  of  sorted  minerals. 

3.  Table  of  sorted  rocks. 

4.  Making  of  rounded  stones  illustrated. 

5.  How  sharp  stones  came  to  be. 

6.  Metals  and  their  properties. 

7.  Molecules  illustrated. 

8.  Crystals,  and  how  they  grow. 

9.  Minerals. 

10.  Rock  making,  physical  agencies. 

11.  Rock  making,  organic  agencies,  and  metamor- 
phism. 

My  arrangement  of  material,  experiments,  maps, 
charts,  etc.,  has  been  as  follows : 

A  long  table,  slightly  slanting  toward  the  front,  or  in 
steps,  was  arranged,  and  x>lain  labels  neatly  printed  by 


ROCK  MAKING. 


357 


the  class  for  each  specimen,  and  large  ones  for  the  prin- 
cipal divisions  or  sections.  The  specimens  were  then 
ranged,  from  back  to  front,  in  six  series,  representing  as 
nearly  as  possible  the  gravel,  sand,  clay,  iron^  lime,  and 
carbon  series. 


MODEL  EXHIBITION  TABLE  OF  ROCK   MAKING. 

Section  J. — Eruptive  and  Dike  Mocks. 

Slags.    Pumice.    Cellular  lava.    Obsidian.    Felsite.    Basalt. 
Trachyte.    Granite  and  Diorite. 

Section  11. — Leveling  Agencies. 


Water 
COj. 


Rock  with  cracks.     Glaciated  rock, 

Rock  split  by  ice.       Glacier  tool. 

Rock  split  by  roots.  Mixed  material.   Crushed 

Expansion  bar.  "  Geo.  Codfish."      rock. 

Heat  and  cold.  Red  clay. 


Rock  with  lichens. 
Minerals  etched  by  roots. 
Rusted  pyrite. 
Pyrite  in  coal. 
Swelled  iron  sulphate. 
Gray  clay.  Air-slacked  lime. 
Distorted  brick. 

Section  III. — Sediments  and  Sorting. 
Gravel.      |  |  Sand.  |  |  Clay.  | 

Illustrations  of  overlapping  deposits  ;  lake  filling ;  deltas,  etc. 

Sectio7i  IV. — Solutions  deposited  (Chemically  Formed  Rocks), 


Scale. 

Siderite. 

Stalactite. 

Bog  iron. 

Stalag- 

Iron test. 

mite. 

Salt. 

Mexican 

"onyx." 

Oolite. 

Limestone 

Dolomite. 

Gypsum. 

House 

plaster. 

Lime  test. 

Section  V. — Fragmental  Rocks. 


Conglom- 

Sand- 

erates. 

stones. 

Breccia. 

Shales. 


358 


SYSTEMATIC  SCIENCE  TEACHING. 


Section  VI. — Modern  Relatives  of  Ancient  Plants  and  Animals. 


Shells. 
Corals. 
Foramini- 

fers. 
Coccoliths. 


Diatoms. 
Sponge 

spicules. 
Polycis- 

tines. 


Lichens. 

Ferns. 

Lycopods. 

Equisetura. 

Conifers. 


Section  VII. — Eocks  formed  by  Plants  and  Animals 


Fossilifer- 

ous  lime 

rock. 
Nummu- 

litic  lime 

rock. 
Chalk. 


(Organically). 
Diatom- 
earth. 
Flint. 
Chert. 


Sphagnum 
and  peat. 
Black  shale. 
Soft  coal. 
Fossilplants 


Section  VIII. — Metamorphic  Agencies  illustrated. 


Arch  (lateral  pressure).    Wrinkles  in 


cloth— tallow 
—clay— lard 


Cracked  and  rubbed 
rocks. 


Diagram 
of  up- 
heaval. 

Mela- 
phyre. 

Amygda- 
loid. 


Hot  water. 

Geysers. 

Geyserite. 

Veins. 

Crystals 

from 

veins. 
Agates. 
Geodes. 


Heat  (dry). 
Earthquakes 

illustrated 
Faults. 
Dikes 

through 

rocks. 
Black  shale 

burned 

white. 
Red  brick. 


Coal  heated 
becomes 
coke,  tar, 
gas. 


Firm. 

Conglom- 
erates. 

Serpen- 
tine. 


Section  IX. — Results  of  Metamorphism, 


Gypsum. 

Marbles : 
Brown, 
Red, 
White. 


Quartzite. 


Hematite. 
Magnetite. 


Slates. 

Anthracite. 

Mica  schist. 

Petroleum. 

Hornblende 

Natural  gas 

schist. 

Graphite. 

Talcose 

Diamond. 

schist. 

Chlorite 

.schist. 

Gneiss. 

Granite. 

Section  X.^The  Earth  of  To-Day  fitted  for  Man. 


ROCK  MAKING.  359 

When  all  is  ready,  or  at  the  proper  time,  send  out  in- 
vitations to  the  parents  and  friends  to  an  exhibition  that 
I  am  sure  will  prove  enjoyable. 

Notebooks,  diagrams,  etc.,  made  by  the  pupils  should 
also  be  exhibited  at  this  time. 

Material  put  away.— See  Step  XXXVII. 

Eesults  of  the  course  in  Minerals  and  Rocks. 

Especially  the  training  of  the  power  of  decision. 

An  introduction  to  chemistry  and  physics. 

A  great  field  of  knowledge  opened  up  and  the  way 
cleared  for  the  profitable  study  of  geology,  etc. 

An  interesting  avocation  made  possible. 

In  the  nine-year  course  as  outlined,  342  exercises  have 
been  arranged,  taking  about  150  hours  of  school  time,  or 
one  sixtieth  of  the  whole. 

Considering  the  educational  value  of  the  above  re- 
sults, and  that  the  tedium  of  school  confinement  has  been 
relieved  and  other  work  better  done  because  of  interest 
in  this,  it  has  been  time  well  spent. 


STEP  XLIX.— ANIMALS.    ' 

Groups  or  Classification. 

Object. — Familiarity  with  a  number  of  types  has  now 
placed  the  pupil  in  the  position  where  he  can  make  in- 
telligent comparisons  and  detect  those  resemblances  and 
differences  which  are  the  basis  of  true  classification. 
Let  this  be  individual  work  on  specimens,  as  only  so  can 
the  most  valuable  results  be  gained. 

Time.— About  thirty  to  forty  lessons  of  thirty  minutes 
each  at  any  time  of  the  year. 

Material. — Quite  a  stock  will  be  required  to  do  effect- 
ive work  and  keep  a  class  of  twenty  to  twenty-five  all 
busy.  The  gathering  of  this  must  be  begun  at  least  a 
year  in  advance,  or  a  high  price  be  paid,  and  even  then 
the  material  will  not  be  in  proper  shape.  The  teacher 
will  also  lack  the  inspiration  which  comes  from  person- 
ally made  collections. 

The  following  material  has  proved  satisfactory  in 
years  of  use.  but  can  be  varied  without  serious  loss  in 
efficiency.  Cheapness  and  durability  must  always  be 
important  items  in  selecting.  Have  ten  each  of  the  fol- 
lowing : 

Red  coral  (precious)  fragments. 

White  coral  (madrepore)  fragments. 

Collection  of  corals  to  sort.  (These  collections  should 
in  each  case  have  several  representatives  of  the  types 
studied  and  also  of  other  types,  so  that  the  pupil  may 
have  a  little  practice  in  using  his  newly  discovered  key 
to  the  classification.) 
360 


ANIMALS.  361 

Earthworms,  each  in  glass  vial  (of  four-per-cent  for- 
maline solution). 

Leeches,  each  in  glass  vial. 

Sea  worms  (Nereis,  etc.)  in  vials. 

Starfish  (common  sorts,  as  Aster i as),  small,  dry. 

Serpent  stars,  small  and  dry. 

Collection  of  various  starfish  to  sort. 

Sea  urchins  (Echinus),  spineless  tests,  dry. 

Cake  urchins  (Clypeaster),  small,  dry  tests. 

Collection  of  various  echinoderms  to  sort. 

Sow  bugs  (Oniscus),  in  vials. 

Crayfish,  injected  (see  directions  in  Step  IX  for  mak- 
ing dry,  yet  flexible  material  for  study). 

Centipeds,  some  native  form,  in  vials. 

Julius  worms,  in  vials. 

Locusts,  on  pins,  with  wings  of  one  side  set,  larvae  in 
vials. 

Libellula,  on  pins,  with  wings  set,  larvae  in  vials. 

Squash  bugs  on  pins,  larvae  in  vials. 

Ant  lions  (caddis  fly  or  lace  fly),  on  pins,  larvae  in 
vials. 

Meat  flies,  on  pins,  maggots  and  pupa  cases  in 
vials. 

Beetles  (any  large  common  kind),  on  pins,  grubs  and 
pupae  in  vials. 

Bees  (or  wasps),  on  pins,  larvae  and  pupae  in  vials. 

Butterfly,  wings  set,  caterpillars  and  pupae  in  vials. 

Collection  of  several  of  each  order  of  insects,  to 
sort. 

Oyster,  paired  shells. 

Fresh-water  clam,  paired  shells. 

Salt-water  clam  (Venus,  etc.),  paired  shells. 

Collection  of  bivalves,  in  paired  shells,  to  sort. 

Gasteropods,  with  canal  to  lip  (stromb,  murex,  etc.). 

Gasteropods,  lip  entire  (limnoea,  helix,  etc.). 

Collection  of  many  univalves  to  sort. 


362  SYSTEMATIC  SCIENCE  TEACHING. 

Perch,  small  and  fresh,  mounted  or  in  formaline 
fluid. 

Sturgeon  or  garpike,  same  state. 

Goldfish,  salmon,  or  pickerel,  same  state. 

Spotted  (or  tiger)  salamanders,  in  formaline  fluid. 

Frogs  and  tadpoles,  fresh  or  in  fluid. 

Lizards  or  chameleons,  fresh  or  in  fluid. 

Snakes  (small),  fresh,  in  fluid  or  mounted. 

Alligators  (small),  in  fluid  or  mounted. 

Turtles,  mounted,  injected,  or  fluid. 

Blackbirds,  skins  or  mounted. 

Collection  of  bird  skins  for  comparison  with  black- 
bird and  each  other. 

Mammals — rats,  mice,  squirrels,  bats,  and  domestic 
animals— can  usually  be  had  fresh  or  stuffed,  and  markets 
will  frequently  supply  material  for  comparative  study. 

The  work  on  mammals  must  depend  on  the  available 
material ;  in  lack  of  any,  omit. 

Cost.— There  will  be  500  or  more  specimens  in  the 
above  list,  which  will  average  about  ten  cents  each,  or 
$50  for  all.  The  depreciation  will  be  about  ten  per  cent 
each  year  of  use,  but  the  specimens  brought  in  by  inter- 
ested pupils  and  a  wide-awake  instructor  will  ordinarily 
cause  gain  rather  than  loss.  In  any  case,  the  cost  is  very 
small  per  pupil  in  comparison  with  the  valuable  training 
and  added  interest  in  wholesome  things  which  is  gained. 
Good  work  can  be  done  with  a  smaller  supply,  a  single 
specimen  of  some  of  the  rarer  animals  sufficing,  but  the 
delay  and  loss  of  time  to  the  pupils  makes  such  saving 
highly  expensive. 

Store  in  Cigar  Boxes.— These  cost  nothing,  and  rarely 
admit  vermin.  Label  on  the  end,  so  as  to  stack  them  up 
on  shelves  and  still  admit  of  ready  flnding. 

Vials  and  bottles  of  material  in  fluid  can  stand  close 
together  in  coverless  boxes  or  trays.  Label  them  on  the 
corks,  as  w^ell  as  on  the  sides. 


ANIMALS.  363 

Books. — Morse's  First  Book  in  Zoology  is  still  the  best 
real  aid  for  the  cost.  Orton's  Comparative  Zoology  (1894 
edition),  Standard  Natural  History,  Holder's  Zoology,  and 
Jordan's  Manual  of  North  American  Vertebrates,  are  also 
helpful.     Have  ten  copies  each  of  Morse  and  Jordan. 

Cards. — The  material  being  gathered  and  needed  sub- 
stitution made,  proceed  to  prepare  the  following  set  of 
cards  to  direct  the  individual  work.  These  must  be  du- 
plicated to  ten  in  number,  and  written  very  plainly,  or, 
better  still,  printed : 

No.  1.  Find  the  resemblance  and  difference  between 
red  coral  and  white  coral,  recording  the  same  in  your 
notes. 

No.  2.  Classify  the  collection  of  corals  into  two  sets  to 
agree  with  No.  1,  and  bring  to  the  instructor  for  ap- 
proval. 

No.  3.  Compare  the  three  worms  given  (as  with  the 
corals). 

No.  4.  Compare  two  kinds  of  starfish,  as  in  No.  1. 

No.  5.  Sort  the  collection  of  starfish,  as  in  No.  2. 

No.  6.  Compare  two  kinds  of  sea  urchins. 

No.  7.  Sort  the  collection  of  sea  urchins. 

No.  8.  Find  as  many  points  of  resemblance  as  possi- 
ble between  a  starfish  and  a  sea  urchin. 

No.  9.  Compare  a  sow  bug  and  a  crayfish. 

No.  10.  Compare  a  centiped  and  a  milleped. 

No.  11.  Compare  a  locust,  a  libellula,  and  a  squash 
bug. 

No.  12.  Compare  an  ant  lion,  a  fly,  a  beetle,  a  bee,  and 
a  butterfly. 

No.  13.  Arrange  a  collection  of  mixed  insects  accord- 
ing to  the  basis  discovered  in  Nos.  11  and  12.  In  what 
points  are  they  all  alike  f 

No.  14.  Find  resemblances  between  groups  9  to  12 
inclusive  by  a  study  of  a  crayfish,  a  centiped,  and  an 
insect. 


364  SYSTEMATIC  SCIENCE  TEACHING. 

No.  15.  Compare  a  clam  shell  and  a. snail  shell  (see 
Orton,  p.  134). 

No.  16.  Compare  a  clam  shell  and  an  oyster  shell. 

No.  17.  Compare  a  fresh-water  clam  shell  and  a  sea 
clam  shell. 

No.  18.  Arrange  the  collection  of  bivalve  shells  in 
three  groups,  corresponding  to  the  oyster,  fresh-water 
clam,  and  salt-water  clam. 

No.  19.  Compare  stromb  and  helix  shells. 

No.  20.  Sort  a  collection  of  univalve  shells  into  two 
groups  corresponding  to  those  of  No.  19. 

No.  21.  Find  resemblances  between  the  clam,  oyster, 
and  snail. 

No.  22.  Examine  this  perch,  dissecting  carefully,  and 
comparing  with  Orton,  pp.  61,  83, 100,  107,  110,  135,  148, 
158,  172,  184,  311,  312.  Analyze  by  Jordan's  Manual,  and 
use  the  glossary  for  unfamiliar  terms. 

No.  23.  Compare  a  goldfish,  a  perch,  and  a  sturgeon. 
In  what  points  are  these  three  fish  alike. 

No.  24.  Examine  a  frog.  Use  Orton,  pp.  61,  82,  100, 
108,  119,  126,  172,  184.  Analyze  by  Jordan,  and  use  glos- 
sary for  new  terms. 

No.  25.  Compare  a  frog  and  a  salamander,  and  decide 
in  what  points  amphibians  are  alike. 

No.  26.  Examine  a  snake.  Use  Orton,  pp.  54,  61,  67, 
68,  73,  82,  100,  108,  110,  118,  119,  135,  150.  Analyze  by 
Jordan,  and  use  glossary. 

No.  27.  Compare  a  snake,  a  lizard,  a  turtle,  and 
an  alligator,  and  decide  in  what  points  reptiles  are 
alike. 

No.  28.  Examine  a  blackbird.  Use  Orton,  pp.  54,  62, 
84,  100,  109,  110,  118,  137,  150.    Analyze  by  Jordan,  using 


No.  29.  Compare  a  blackbird,  a  duck,  a  hen  (add 
other  typical  birds,  if  available),  and  decide  on  resem- 
blances. 


ANIMALS.  365 

No.  30.  Examine  a  rabbit.  Use  Orton,  pp.  54, 62, 68, 70, 
86,  110,  119,  136.     Analyze  by  Jordan,  and  use  glossary. 

No.  31.  Compare  a  rabbit,  a  cat,  a  cow,  and  yourself, 
and  decide  on  points  in  which  all  are  alike. 

No.  32.  Review  notes  on  Nos.  22  to  31,  and  find  points 
in  which  all  are  alike. 

No.  33.  From  memory  write  as  many  points  as  you 
can  in  which  all  animals  are  alike. 

No.  34.  Make  a  study  of  the  resemblances  and  differ- 
ences between  plants  and  animals. 

The  Lessons. 

Notebooks  and  pencils  should  be  had  by  each  pupil ; 
the  book  square  rather  than  long  (10  x  12  cm.),  and 
opening"  at  the  end. 

Model  Notes. — It  is  important  that  correctness  and 
neatness  shall  be  observed  by  all,  and  this  can  best  be 
secured  by  a  model  at  the  beginning.  See  page  281  and 
proceed  as  follows  : 

1.  Distribute  the  specimens  of  coral  so  that  each  pair 
of  pupils  may  have  specimens. 

2.  Place  at  the  top  of  the  blackboard  (pupils  place  in 
notebooks) : 

Corals  Compared. 

Differences. 
Resemblances.   Points  noticed.   Red  Coral   White  Coral 

8.  Under  "  Points  noticed  "  list  all  things  they  can  no- 
tice about  the  specimens,  leaving  space  for  after-thoughts 
below. 

4.  Then  extend,  in  line  with  each  point,  such  remarks 
as  may  be  proper. 

5.  Examine  these  lists  to  see  what  are  the  most 
noticeable  resemblances  and  differences,  and  underline 
such. 


366 


SYSTEMATIC  SCIENCE  TEACHING. 


The  page  in  the  notebooks  will  then  resemble  this : 
Corals  Compared. 


Differences. 

Besemblances. 

Points  noticed. 

Bed  Coral. 

White  Coral. 

Color. 

Eed. 

White. 

Branched. 

Shape. 

Surface. 

Furrows. 

Pits. 

Hard. 

Texture. 

Solid. 

Porous. 

Effervesce  = 

Acid  test. 

calcareous. 

In  sea. 

Home. 

About  the 

Tentacles 

In  eights,  and 

In    sixes,    an 

mouth. 

(from  pictures) 

fringed. 

smooth. 

In  middle  of  top 

Mouth  (see 
pictures). 

Next,  with  the  blackboard,  help  the  pupils  to  head  the 
pages  of  their  notebooks  to  (correspond  with  the  cards. 
All  is  now  ready  for  individual  work. 

Let  the  teacher  be  seated  at  a  large  table  on  which 
the  material  is  handy,  with  one  of  the  older  pupils  to 
assist  during  the  starting. 

Call  up  pupil  A,  and  give  the  collection  of  corals  and 
card  2. 

To  the  next  ten  give  card  3  and  the  three  worms,  and 
to  the  rest  of  the  class  card  4  and  the  two  starfishes,  and 
so  on. 

When  A  returns  the  corals,  examine  to  see  that  the 
solid  and  porous  kinds  are  separated,  and,  if  right,  give 
card  3  and  the  worms  ;  or,  if  none  are  in,  give  card  4  and 
the  starfishes. 

Whenever  a  pupil  thinks  he  has  thoroughly  studied 
his  specimens  and  recorded  his  observations,  let  him 
quietly  bring  book  and  specimens  to  the  teacher,  who 
will  glance  over  the  "  resemblances  "  to  see  that  the  pu- 
pil has  discovered  those  by  which  scientists  group  the 


ANIMALS.  367 

specimens,  and  over  the  "  diflPerences  "  to  see  that  enough 
have  been  observed  to  identify  each  kind.  A  dash  of  col- 
ored pencil  under  these  characteristic  points  will  show 
the  pupil  the  essentials  on  which  classification  is  based, 
and  he  can  be  given  the  next  thing  unfinished — in  this 
case,  the  box  of  corals  to  sort. 

Two  difficulties  will  here  begin  which  will  test  the 
tact  and  good  sense  of  any  teacher.  First,  how  to  pre- 
vent the  lazy  and  weak  from  copying  the  approved  notes 
of  the  bright  and  quick.  No  reproof  or  punishment  is  of 
permanent  value.  My  plan  has  been  at  the  start  to  plainly 
point  out  the  serious  damage  it  is  to  the  one  who  copies, 
and  to  stimulate  a  sense  of  pride  and  self-respect  which 
will  forbid  helping  or  being  helped.  This,  added  to  my 
request,  has  rarely  failed,  and  when  it  has  failed  the  pu- 
pil has  punished  himself  beyond  anything  I  could  in- 
flict, and  he  knows  it.  Second,  how  to  encourage  those 
whose  "eyes  see  not,"  and  who  come  time  after  time 
without  having  observed  the  essential  differences  and 
resemblances.  That  such  should  learn  to  be  close  ob- 
servers is  of  importance  in  their  life  work,  and  is  worthy 
of  the  most  serious  effort ;  hence  encourage  them  in  every 
way  to  try  again,  but  do  not  do  their  work  for  them.  It 
may  be  well  in  some  cases  to  lay  aside  the  material  in 
hand  and  select  something  new  till  success  has  brought 
new  courage  and  restored  confidence.  (Shells  have  proved 
helpful  in  this.) 

Varying  ability  and  knowledge  will  soon  spread  the 
class  over  sufficient  ground,  so  that  each  student  who  has 
mastered  one  set  of  material  can  be  supplied  with  the  next 
thing  his  notebook  headings  call  for,  and  the  work  will 
be  easily  carried  forward  by  the  well-informed  and  ex- 
perienced teacher.  Some  pupils  will  develop  almost  the 
intuition  of  a  Linnaeus,  and  be  inconveniently  ahead  of 
the  rest.  To  keep  such  busy,  and  still  reward  energetic 
and  thorough  work,  I  provide  side  issues  (open  only  to 


368  SYSTEMATIC  SCIENCE  TEACHING. 

those  in  advance  of  the  rest)  to  occupy  their  time.  These 
must  be  devised  by  the  instructor  in  accordance  with  his 
equipment,  etc.  I  give  them  my  private  and  larger  col- 
lections to  examine  (and  find  scientific  names  for  the 
specimens),  a  compound  microscope  to  examine  sections 
of  shells,  scales,  etc.,  have  them  find  the  percentage  of 
lime  in  skeletons,  and  make  a  comparative  study  of  scales, 
hair,  and  feathers;  these  are  among  my  tried  and  suc- 
cessful devices. 

When  vertebrates  are  reached,  such  bright  pupils  espe- 
cially enjoy  finding  the  names  of  specimens  by  Jordan's 
book.  Glass  reviews  can  be  held  from  time  to  time,  and 
by  rapid  questions  or  descriptions  the  characters  of  some 
one  class  of  animals  (which  all  have  completed)  may  be 
emphasized. 

Results. — This  work  will  delight  the  pupils  and  sur- 
prise the  teacher  if  approached  in  the  proper  spirit.  Pu- 
pils who  seemed  incapable  of  learning  from  books  have 
in  this  shown  great  acuteness,  and  received  a  new  stimu- 
lus for  less  attractive  subjects,  while  all  have  gained  in 
rapid  and  accurate  observation  and  acquired  zest  for  a 
healthy  avocation. 

General  Conclusion. 

In  the  nine  years'  work  outlined,  about  350  exercises, 
'^consuming  120  hours  (one  seventy-fifth  of  the  9,000  or 
more  a  child  usually  spends  in  school  up  to  the  age  of 
fifteen),  have  been  given  to  these  animal  lessons. 


INDEX 


Roman  numerals  refer  to  Steps,  others  to  pages. 


Absorption  of  heat,  185. 

Of  water,  303. 
Adhesion,  134. 
Air,  83, 
Animals :  Types,  XXVII,  31. 

In  winter  quarters,  XXIX,  96. 

Man  and  environment,  XXXII, 
162. 

Life   histories,    XXXVIII,    271, 
and  XXXIX,  276. 

Classitication,  XLIX,  360. 

Eelation  to  plants,  93. 
Ants,  102. 
Aphis,  102. 

Astronomy.    (See  Stars.) 
Axes  of  crystals,  231. 

Barometer,  112. 

Bat,  100. 

Birds.     (See  Animals.) 

Relation  to  plants,  91,  92. 
Blowpipe  work,  251,  267. 
Blue  jay, 100. 
Boy  lessons,  XXVII,  31. 
Brooks  and  rivers,  84. 
Bumblebee,  101. 
Buoyancy,  153  ft'.,  260. 
Butcher  bird,  100. 
Butterfly,  102,  273. 
25 


Cards  for  experiment,  etc.,  120,324, 

363. 
Caterpillar,  60, 102. 
Cavendish's  experiment,  108. 
Central  forces,  XXX,  104. 
Chipmunk,  99. 
Clams,  70, 103, 273. 
Clay  work,  23. 

Cleavage  of  minerals,  248,  254. 
Cohesion,  133. 
Coins,  XLIII,  290. 
Cold  and  plants,  82. 
Collections  omitted,  178. 
Colors,  metallic,  16,  246. 

Of  flames,  212. 

Of  minerals,  246. 

Of  planets,  7. 

Ofplants,  89,  90,  94. 

Of  spectrum,  213. 
Comets,  10. 

Conduction  of  heat,  157, 188. 
Conservation  of  energy,  147, 148. 
Constellations,    10,    115,  219,   288, 

335. 
Cooking  and  utensils,  172. 
Coral,  75,  343. 
Corn  and  beans,  XLI,  279. 
Cow,  33. 
Cow  blackbird,  100. 

369 


370 


SYSTEMATIC  SCIENCE  TEACHING. 


Crayfish,  62, 103,  273. 

Field  work,  plants,  194,  328. 

Crow,  101. 

Stars,  287. 

Crystals,  axes  of,  231. 

Fire  making,  171. 

Clay  work,  XXVI,  23. 

Fish,  53, 101,  274. 

Crystallization,  227  tf. 

Flame,  18,  209,  211. 

Models  made,  222  fF. 

Fly,  102. 

Planes  of  symmetry,  232. 

Food,  of  man,  165. 

Study  of,  XXXVl,  222. 

Of  plants,  191  ff. 

Systems  of,  282  ff. 

Form  (solid),  XXVI,  23. 

Friction,  144,  312,  352. 

Darkness  and  plants,  82. 

Frog,  50, 101,  274. 

Deltas,  315. 

Fruits,  92,  94,  XL,  277. 

Dew,  83. 

Fusibility:  Metals,  16. 

Diaphaneity,  247. 

Kocks,  299. 

Drawing:   Corn  and  Beans,  XL  I, 

279. 

Gases,  136,  209. 

Fruit,  XL,  277. 

Geography.    (See  Chart,  vol.  i.) 

Life      histories      of      animals. 

Early  history  of  the  earth,  XLII, 

XXXVllI,  271;    XXXIX, 

284. 

276. 

Earth  making,  XLIV,  292. 

Eocks,    XLIV,    292;     XLVIII, 

Earth  making  (cont.),  XLVIII, 

337. 

337. 

Solar  system,  XXIV,  1. 

Man  at  home,  XXXII,  162. 

Winter     quarters     of      plants. 

Plants,  85  ff. 

XXXIV,  179. 

Geometric  form,  23. 

Drought,  84. 

Glaciers,  309  tf. 

Duck,  101. 

Goose,  101. 

Gopher,  99. 

Early  history  of  the  earth,  XLII, 

Grasshopper,  102. 

284. 

Guide  to  study  of  minerals,  245- 

Earthmaking,XLlV,292;  XLVIII, 

251. 

337. 

Earthworm,  73,  103,  273. 

Hardness  :  Of  metals,  16. 

Ecliptic,  10. 

Of  minerals,  246. 

Electricity,  142, 143. 

Hawk,  101. 

English  sparrow,  100. 

Heat,  18,  82, 144  fi.,  185  ff.,  287, 302, 

Ether  of  space,  206  fl'. 

349  ff. 

Evaporation,  183. 

Hen,  39,  274. 

Expansion  by  heat,  150  if.,  302. 

Hibernation,  99  ff. 

Experimentation,  117  tf. 

Honey  bee,  101. 

Hornet,  102. 

Field  work,  minerals,  270. 

Humming  bird,  101. 

INDEX. 


371 


Inertia,  106. 
Insects,  101,  273,  363. 

and  plants,  90,  91. 
Iron,  16. 

Deposits,  318,  354. 

Test,  307. 

Kingfisher,  101. 

Laplace,  196  ff. 

Latitude  and  plants,  86. 

Lenses,  204  it". 

Libellula,  102. 

Life  histories  of  animals,  271,  276. 

Light :  A  mode  of  motion,  146, 198. 

Chemical  rays,  80, 146. 

Dispersion,  195  If. 

Reflection,  201. 

Kefraction,  205  tf. 

Relation  to  plants,  80. 

Speed  of,  10,  204. 
Lime  deposits  and  stone,  316  ff., 
343. 

Metaraorphism,  353. 

Solution,  306  If. 
Liquids,  136. 

Pressure  of,  320. 
Luster  of  minerals,  232,  248. 

Magnets,  15,  108, 140  ff.,  247. 
^an,  XXXII,  162. 

Cooking  and  utensils,  172. 

Fire,  171. 

Food,  165. 

Language,  177. 

Permanent  expression,  177. 

Shelter  and  protection,  175. 

Tools  and  weapons,  167. 

Travel  and  transportation,  174. 
Meadow  lark,  100. 
Metals,  XXV,  13. 
Metamorphism,  348  tf. 


Metric    weights     and     measures, 

117  ff.,  255,  259. 
Migration,  99  ff.,  164. 
Mineral  lessons,  XXXVII,  240. 
Mink,  100. 
Mirrors,  203  ff. 
Mole,  100. 

Molecules,  XXXI,  117. 
Moon,  5, 112  ft'.,  217. 
Mosquito,  102. 
Moth,  57, 102. 
Motion,  central,  107  ff. 

Resultant,  109  ff. 
Mountain  making,  349  ff. 
Mountains  and  plants,  85. 
Muskrat,  99. 
Myths,  11, 115,  219. 

Nebulae,  208  ff. 

Original  design,  26. 

Other  systems  than  ours,  XLVII, 

333. 
Owl,  101. 

Parallax,  334. 
Pendulum,  135. 
Perch,  101. 

Permanent  expression,  178. 
Physics.    (See  Absorption,  Elec- 
tricity,   Color,    Gravita- 
tion, Heat,  Light,  Magnet- 
ism, Molecular  Structure, 
Motion,  Radiation,  Sound.) 
Planets,  relation  of,  to  gravitation, 
104  ff. 
Size,  distance,  etc.,  of,  1  ff. 
Plant  beetle,  102. 
Plants,  classification  : 
Corn  and  beans,  XLT,  279. 
Families  of  spring,  XL  V,  322. 
Families  of  autumn,  XLVI,  330. 


372 


SYSTEMATIC  SCIENCE  TEACHING. 


Plants : 

Food  of,  191. 

Fossil  relations,  345  ff. 

Fruits,  XL,  277. 

lielationship,  XXVIII,  79. 

Winter  quarters  of,  XXXIV,  179. 
Prairie  chicken,  101. 
Public  celebrations:  Plants,  181. 

Rocks,  356. 

Star  party,  288. 

Stars,  335. 

Quail,  101. 

Rabbit,  98. 

Raccoon,  98. 

Radiation,  of  heat,  185  ff. 

Of  light,  198  tf. 
Rain,  83. 
Reflection,  of  heat,  187. 

Of  light,  202  if. 
Relationships  of  animals,  XXIX, 
96;  XLIX,  360. 

Ofman,  XXXII,  162. 

Ofplants,  XXVIII,  79;  XXXIV, 
179;  XLI,  279;  XLV,  322; 
XLVI,  330. 

Of  the  Earth,  XXIV,  1 ;  XLVII, 
333. 
Robin,  100. 
Rocks,  XLIV,  292;  XL VIII,  337. 

Chemically  formed,  316. 

Composition  of,  299. 

Fragmental,  320. 

Metamorphic,  348  ft*. 

Organically  formed,  343  ft". 

Specimens  for  study,  293,  338. 

Volcanic,  296  ff. 

Sea  and  plants,  87. 
Sharp     stones     (continued),    160, 
301. 


Shelter  and  protection,  175. 
Skunk,  99. 
Snail,  67,  103,  274. 
Snake,  47, 101,  274. 
Snipe,  101. 
Snowbird,  100. 
Soil,  kinds  of,  84. 

Made  by  worms,  74. 

Made  by  crayfish,  66. 
Solar  system,  XXX,  104. 
Solid  form,  XXVI,  23. 
Sorting  animals,  363. 

Metals,  21. 

Minerals,  263,  266. 
Sound,  145. 
Specific  gravity,  250,  255. 

Metals,  16. 

Minerals,  259. 

Rocks,  299. 
Spectroscope,  209  ff. 
Spider,  102,  273. 
Sponge,  77. 
Springs,  308. 
Squash  bug,  102,  273. 
Squirrel,  99. 
Starfish,  75,  273. 

Stars    and    earth,    solar    system, 
XXIV,  1. 

Gravitation,  etc.,  XXX,  104. 

Light,  XXXV,  195. 

Early  history  of  the  earth,  XLII, 
284. 

Other  systems  than  ours,  XLVII, 
333. 

Falling,  112. 

Lantern,  116. 

Maps,  116. 
Steel  making,  209  ff.     . 
Steps  XXIV,  The  Solar  System,  1 

XXV,  Metals,  13. 

XXVI,  Solid  Form,  23. 

XXVII,  Typical  Animals,  31. 


INDEX. 


373 


Steps    XXVIII,    Plant    Eelation- 
ships,  79. 

XXIX,  Animals  in  Winter  Quar- 
ters, 96. 

XXX,  Gravitation  and  Solar 
System,  104. 

XXXI,  Molecules,  117. 

XXXII,  Man,  162. 
XXXIII  (omitted),  178. 

XXXIV,  Winter  Quarters  of 
Plants,  179. 

XXXV,  What  the  Telescope  re- 
veals, 195. 

XXXVI,  Crystals,  222. 

XXXVII,  Minerals,  240. 

XXXVIII,  Animals,  Life  Histo- 
ries of,  271. 

XXXIX,  Animals,  Life  Histories 
of  (continued),  276. 

XL,  Fruits,  277. 

XLI,  Corn  and  Beans,  279. 

XLII,  Early  History  of  the 
Earth,  284. 

XLIII,  Coins,  290. 

XLIV,  Book  Making  (Physical), 
292. 

XLV,  Plant  Families  (Spring), 
322. 

XLVl,  Plant  Families  of  Au- 
tumn, 330. 

XLVII,  Other  Systems  than 
Ours,  333. 


Steps  XL VIII,  Rock  Making  (com- 
pleted), 337. 
XLIX,    Animal    Classification, 
360. 

Sun,  1,  217  flf. 

Swallow,  100. 

Telescope,  195  ff. 
Tenacity,  of  metals,  16. 

Of  minerals,  248. 
Thermometer,  150  ft". 
Tides,  113,  287. 
Time  and  plants,  86, 191. 
Tools  and  weapons,  167. 
Travel  and  transportation,  174. 
Turtle,  101. 

Utensils  and  cooking,  172. 

Venus,  3. 
Vertebrate  types,  57. 

Warbler,  100. 
Weighing,  259  ff. 
Weight,  108, 134. 
Wind  and  plants,  83. 
Winter      quarters      of     animals, 
XXIX,  96. 
Ofplants,  XXXIV,  179. 
Woodchuck,  100. 
Woodpecker,  101. 
Work,  XXX,  104. 


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gold  of  the  Klondike  has  led  to  a  better  knowledge  of  the  region, 
while  within  a  short  time  we  shall  have  much  more  exact  geo- 
graphical information  concerning  the  numerous  islands  which 
make  up  the  Philippines.  The  want  which  is  indicated  will  be 
met  by  **The  International  Geography,"  a  convenient  volume 
for  the  intelligent  general  reader,  and  the  library  which  pre- 
sents expert  summaries  of  the  results  of  geographical  science 
throughout  the  world  at  the  present  time.  The  book  contains 
nearly  five  hundred  illustrations  and  maps  which  have  been 
specially  prepared.  It  is  designed  to  present  in  the  compact 
limits  of"  a  single  volume  an  authoritative  conspectus  of  the 
science  of  geography  and  the  conditions  of  the  countries  at  the 
end  of  the  nineteenth  century. 

D.    APPLETON     and      company,     new     YORK. 


MCMASTER'S  FIFTH  VOLUME. 

History  of  the  People  of  the  United 
States. 
By  Prof.  John  Bach  McMaster.    Vol.  V.    8vo. 
Cloth,  with  Maps,  ^2.50. 

The  fifth  volume  of  Prof  J.  B.  McMaster's 
"History  of  the  People  of  the  United  States" 
will  cover  the  time  of  the  administrations  of  John 
Quincy  Adams  and  Andrew  Jackson,  and  will  de- 
scribe the  development  of  the  democratic  spirit, 
the  manifestations  of  new  interest  in  social  prob- 
lems, and  the  various  conditions  and  plans  pre- 
sented between  1821  and  1830.  To  a  large  extent 
the  intimate  phases  of  the  subjects  which  are  treat- 
ed have  received  scant  attention  heretofore.  A  pe- 
culiar interest  attaches  to  the  various  banking  and 
financial  experiments  proposed  and  adopted  at 
that  time,  to  the  humanitarian  and  socialistic 
movements,  the  improvements  in  the  conditions 
of  city  life,  to  the  author's  full  presentation  of  the 
literary  activity  of  the  country,  and  his  treatment 
of  the  relations  of  the  East  and  West.  Many  of 
these  subjects  have  necessitated  years  of  first-hand 
investigations,  and  are  now  treated  adequately  for 
the  first  time. 

D.     APPLETON     AND      COMPANY,     NEW     YORK. 


APPLETONS^  HOME-READING  BOOKS. 

Edited  fay  W.  T.  HARRIS,  A,  M.,  LL.  D»,  U.  S.  Commissionet 
of  Education. 

CLASSED   IN  FOUR   DIVISIONS,   AS  FOLLOWS  : 

The  First  comprises  natural  hisMry,  including  popular  treatises  on  plants  and  ani- 
mals, and  also  descriptions  of  geographical  localities,  all  of  which  pertain  to  the  study 
of  geography  in  the  common  schools.  Descriptive  astronomy,  and  anything  that  relates 
to  organic  Nature,  comes  under  this  head. 

The  Second  includes  whatever  relates  to  natural  philosophy,  statics,  dynamics,, 
properties  of  matter,  and  chemistry,  organic  and  morganic. 

The  Third  covers  history,  biography,  ethnology,  ethics,  civics,  and  all  that  relates 
to  the  lives  of  individuals  or  of  nations. 

The  Fourth,  works  of  general  literature  that  portray  human  nature  in  the  form 
of  feelines.  emotions,  and  the  various  expressions  of  art  and  music. 

Net. 

The  Story  of  the  Birds.    J.  N.  Baskett $0.65 

The  Story  of. the  Fishes.     J.  N.  Baskhtt 75 

The  Plant  World.     Fkank  Vincent 60 

The  Animal  World.     Frank  Vincent 60 

The  Insect  World.     C.  M.  Weed 60 

The  Story  of  Oliver  Twist.     Ella  B.  Kirk 60 

The  Story  of  Rob  Roy.     Edith  T.  Harris 60 

In  Brook  and  Bayou.     Clara  Kern  Bavliss 60 

Curious  Homes  and  their  Tenants.     James  Carter  Beard         .        .        .(><, 

Crusoe's  Island.     F.   A.  Ober 65 

Uncle  Sam's  Secrets.     O.  F.  Austin 75 

The  Hall  of  Shells.     Mrs.  A.  S.  Hakdv 60 

Nature  Study  Readers.     J.  W.   Troeger. 

Harold's  First  Discoveries.     Book  I 2^ 

Harold's  Rambles.     Book  II 40 

Harold's  Quests.     Book  III 50 

Harold's  Explorations.     Book  IV 

Harold's  Discussions.     Book  V 

Uncle  Robert's  Geography.     Francis  W.   Parker  and 
Nellie  L.  Helm. 

Playtime  and  Seedtime.     Book  I 3a 

On  the  Farm.     Book  II 4a 

Uncle  Robert's  Visit.     Book  III 50 

Rivers  and  Winds.     Book  IV 

Mountain,  Plain,  and  Desert.     Book  V 

Our  Own  Continent.     Book  VI 

News  from  the  Birds.     Leander  S.  Keyser 60 

Historic  Boston  and  its  Neighborhood.     Edward  Everett  Hale     .        .50 

The  Earth  and  Sky.     Edward  S.  Holden 28 

The  Family  of  the  Sun.     Edw.ard  S.  Holden  .....         .50 

Some  Great  Astronomers.     Edward  S.  Holden 60 

About  the  Weather.     Mark  W.  Harrington ".        .65 

Stories  from  the  Arabian  Nights.     Adam  Singleton 65 

Our  Country's  Flag  and  the  Flags  of  Foreign  Countries.     Edward 

S.  Holden 80 

Our  Navy  in  Time  of  War.     Franklin  Matthfws         •        •        •        •        '75 
The  Chronicles  of  Sir  John  Froissart.     Adam  Singleton    ...        .65 

The  Storied  West  Indies.     F.  A.  Ober 75 

Uncle  Sam's  Soldiers.    O.  P.  Austin 75 

Others  in  preparation. 

D.     APPLETON     AND     COMPANY,     ^^EW    YORK. 


THE  LIBRARY  OF  USEFUL  STORIES* 

lUustratcd.     J6mo.     Cloth,  40  cents  per  volume^ 
NOPV  READY. 

The  Story  of  the  Living  Machine.    By  H.  w.  Conn. 
The  Story  of  Eclipses.    By  g.  f.  chambers. 
The  Story  of  the  British  Race.    By  John  Munro,  c.  e. 
The  Story  of  Geographical  Discovery.     By  Joseph 

Jacobs. 

The  Story  of  the  Cotton  Plant.  By  F.  Wilkinson,  f.g.s. 

The   Story   of  the    Mind.     By  Prof.  J.  mark  Baldwin. 
The  story  of   Photography.      By  Alfred  T.  Story. 

The  story  of  Life  in  the  Seas.    By  Sidney  j.  hickson. 

The  story  of  Germ  Life.    By  Prof.  h.  w.  Conn. 

The  Story  of  the  Earth's  Atmosphere.    By  Doug- 
las Archibald. 

The  Story  of  Extinct  Civilizations  of  the  East. 

By  Robert  Anderson,  M.  A.,  F.  A.  S. 

The  Story  of  Electricity.    By  John  munro,  c.  e. 
The  Story  of  a  Piece  of  Coal.   By  e.  a.  martin,  f.g.s. 
The  Story  of  the  Solar  System.    By  c.  f.  Chambers, 

F.  R.  A.  S. 

The  Story  of  the  Earth.    By  h.  g.  seeley,  f.  r.  s. 
The  Story  of  the  Plants.    By  grant  Allen. 
The  Story  of  "  Primitive  "  Man.    By  Edward  clodd. 
The  Story  of  the  Stars.     By  G.  F.  Chambers,  f.  r.  a.  s. 

OTHERS   IN   preparation, 

D.   appleton    and    company,    new    YORIC. 


THE  CONCISE  KNOWLEDGE  LIBRARY 

Each,  small  Svo^  half  leather,  $2*00, 

The  History  of  the  World, 

From  the  Earliest  Historical  Time  to  the  Year  1898.  By 
Edgar  Sanderson,  M.  A.,  author  of  <*A  History  of  the  British 
Empire/*  etc. 

The  Historical  Reference-Book. 

Comprising  a  Chronological  Table  of  Universal  History,  a 
Chronological  Dictionary  of  Universal  History,  and  a  Biograph- 
ical Dictionary.  With  Geographical  Notes.  For  the  use  of 
Students,  Teachers,  and  Readers.  By  Louis  Heilprin.  Fifth 
edition,  revised  to  1898. 

Natural  History. 

By  R.  Lydekker,  B.  A.;  W.  F.  Kirby,  F.  L.  S.;  B.  B.  Wood- 
ward, F.  L.  S. ;  R.  KiRKPATRicK  ;  R.  I.  PococK  ;  R.  Bowdler 
Sharpe,  LL.  D.;  W.  Garstang,  M.  A.;  F.  A.  Bather,  M.  A., 
and  H.  M.  Bernard,  M.  A.  Nearly  800  pages,  and  500 
Illustrations  drawn  especially  for  this  work. 

Astronomy. 

Fully  illustrated.  By  Agnes  M.  Clerke,  A.  Fowler,  F.R.A.S., 
Demonstrator  of  Astronomical  Physics  of  the  Royal  College  of 
Science,  and  J.  Ellard  Gore,  F.  R.  A.  S. 


D  .      /APPLET  0,^?--^  TTS-^  OMPANY,     NEW      YORK 

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